Merge pull request #22088 from owncloud/share2_ishare

[Share 2.0] Pass around userid/groupid/federatedid

13 files changed, 603 insertions, 690 deletions

diff --git a/apps/files_sharing/api/share20ocs.php b/apps/files_sharing/api/share20ocs.php
index 63c49b926bf..d7c5d004d9c 100644
--- a/apps/files_sharing/api/share20ocs.php
+++ b/apps/files_sharing/api/share20ocs.php
@@ -26,35 +26,41 @@ use OCP\IRequest;
 use OCP\IURLGenerator;
 use OCP\IUser;
 use OCP\Files\IRootFolder;
+use OCP\Share\IManager;
 
 use OCP\Share\Exceptions\ShareNotFound;
 use OCP\Share\Exceptions\GenericShareException;
 
 class Share20OCS {
 
-	/** @var \OC\Share20\Manager */
+	/** @var IManager */
 	private $shareManager;
-
 	/** @var IGroupManager */
 	private $groupManager;
-
 	/** @var IUserManager */
 	private $userManager;
-
 	/** @var IRequest */
 	private $request;
-
 	/** @var IRootFolder */
 	private $rootFolder;
-
 	/** @var IUrlGenerator */
 	private $urlGenerator;
-
 	/** @var IUser */
 	private $currentUser;
 
+	/**
+	 * Share20OCS constructor.
+	 *
+	 * @param IManager $shareManager
+	 * @param IGroupManager $groupManager
+	 * @param IUserManager $userManager
+	 * @param IRequest $request
+	 * @param IRootFolder $rootFolder
+	 * @param IURLGenerator $urlGenerator
+	 * @param IUser $currentUser
+	 */
 	public function __construct(
-			\OC\Share20\Manager $shareManager,
+			IManager $shareManager,
 			IGroupManager $groupManager,
 			IUserManager $userManager,
 			IRequest $request,
@@ -78,22 +84,24 @@ class Share20OCS {
 	 * @return array
 	 */
 	protected function formatShare(\OCP\Share\IShare $share) {
+		$sharedBy = $this->userManager->get($share->getSharedBy());
+		$shareOwner = $this->userManager->get($share->getShareOwner());
 		$result = [
 			'id' => $share->getId(),
 			'share_type' => $share->getShareType(),
-			'uid_owner' => $share->getSharedBy()->getUID(),
-			'displayname_owner' => $share->getSharedBy()->getDisplayName(),
+			'uid_owner' => $share->getSharedBy(),
+			'displayname_owner' => $sharedBy->getDisplayName(),
 			'permissions' => $share->getPermissions(),
 			'stime' => $share->getShareTime()->getTimestamp(),
 			'parent' => null,
 			'expiration' => null,
 			'token' => null,
-			'uid_file_owner' => $share->getShareOwner()->getUID(),
-			'displayname_file_owner' => $share->getShareOwner()->getDisplayName(),
+			'uid_file_owner' => $share->getShareOwner(),
+			'displayname_file_owner' => $shareOwner->getDisplayName(),
 		];
 
 		$node = $share->getNode();
-		$result['path'] = $this->rootFolder->getUserFolder($share->getShareOwner()->getUID())->getRelativePath($node->getPath());
+		$result['path'] = $this->rootFolder->getUserFolder($share->getShareOwner())->getRelativePath($node->getPath());
 		if ($node instanceOf \OCP\Files\Folder) {
 			$result['item_type'] = 'folder';
 		} else {
@@ -107,13 +115,12 @@ class Share20OCS {
 		$result['file_target'] = $share->getTarget();
 
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER) {
-			$sharedWith = $share->getSharedWith();
+			$sharedWith = $this->userManager->get($share->getSharedWith());
 			$result['share_with'] = $sharedWith->getUID();
 			$result['share_with_displayname'] = $sharedWith->getDisplayName();
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
-			$sharedWith = $share->getSharedWith();
-			$result['share_with'] = $sharedWith->getGID();
-			$result['share_with_displayname'] = $sharedWith->getGID();
+			$result['share_with'] = $share->getSharedWith();
+			$result['share_with_displayname'] = $share->getSharedWith();
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_LINK) {
 
 			$result['share_with'] = $share->getPassword();
@@ -250,14 +257,14 @@ class Share20OCS {
 			if ($shareWith === null || !$this->userManager->userExists($shareWith)) {
 				return new \OC_OCS_Result(null, 404, 'please specify a valid user');
 			}
-			$share->setSharedWith($this->userManager->get($shareWith));
+			$share->setSharedWith($shareWith);
 			$share->setPermissions($permissions);
 		} else if ($shareType === \OCP\Share::SHARE_TYPE_GROUP) {
 			// Valid group is required to share
 			if ($shareWith === null || !$this->groupManager->groupExists($shareWith)) {
 				return new \OC_OCS_Result(null, 404, 'please specify a valid group');
 			}
-			$share->setSharedWith($this->groupManager->get($shareWith));
+			$share->setSharedWith($shareWith);
 			$share->setPermissions($permissions);
 		} else if ($shareType === \OCP\Share::SHARE_TYPE_LINK) {
 			//Can we even share links?
@@ -313,7 +320,7 @@ class Share20OCS {
 		}
 
 		$share->setShareType($shareType);
-		$share->setSharedBy($this->currentUser);
+		$share->setSharedBy($this->currentUser->getUID());
 
 		try {
 			$share = $this->shareManager->createShare($share);
@@ -333,8 +340,8 @@ class Share20OCS {
 	 * @return \OC_OCS_Result
 	 */
 	private function getSharedWithMe($node = null) {
-		$userShares = $this->shareManager->getSharedWith($this->currentUser, \OCP\Share::SHARE_TYPE_USER, $node, -1, 0);
-		$groupShares = $this->shareManager->getSharedWith($this->currentUser, \OCP\Share::SHARE_TYPE_GROUP, $node, -1, 0);
+		$userShares = $this->shareManager->getSharedWith($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_USER, $node, -1, 0);
+		$groupShares = $this->shareManager->getSharedWith($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_GROUP, $node, -1, 0);
 
 		$shares = array_merge($userShares, $groupShares);
 
@@ -361,9 +368,9 @@ class Share20OCS {
 		/** @var \OCP\Share\IShare[] $shares */
 		$shares = [];
 		foreach ($nodes as $node) {
-			$shares  = array_merge($shares, $this->shareManager->getSharesBy($this->currentUser, \OCP\Share::SHARE_TYPE_USER, $node, false, -1, 0));
-			$shares = array_merge($shares, $this->shareManager->getSharesBy($this->currentUser, \OCP\Share::SHARE_TYPE_GROUP, $node, false, -1, 0));
-			$shares  = array_merge($shares, $this->shareManager->getSharesBy($this->currentUser, \OCP\Share::SHARE_TYPE_LINK, $node, false, -1, 0));
+			$shares  = array_merge($shares, $this->shareManager->getSharesBy($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_USER, $node, false, -1, 0));
+			$shares = array_merge($shares, $this->shareManager->getSharesBy($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_GROUP, $node, false, -1, 0));
+			$shares  = array_merge($shares, $this->shareManager->getSharesBy($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_LINK, $node, false, -1, 0));
 			//TODO: Add federated shares
 
 		}
@@ -417,9 +424,9 @@ class Share20OCS {
 		}
 
 		// Get all shares
-		$userShares = $this->shareManager->getSharesBy($this->currentUser, \OCP\Share::SHARE_TYPE_USER, $path, $reshares, -1, 0);
-		$groupShares = $this->shareManager->getSharesBy($this->currentUser, \OCP\Share::SHARE_TYPE_GROUP, $path, $reshares, -1, 0);
-		$linkShares = $this->shareManager->getSharesBy($this->currentUser, \OCP\Share::SHARE_TYPE_LINK, $path, $reshares, -1, 0);
+		$userShares = $this->shareManager->getSharesBy($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_USER, $path, $reshares, -1, 0);
+		$groupShares = $this->shareManager->getSharesBy($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_GROUP, $path, $reshares, -1, 0);
+		$linkShares = $this->shareManager->getSharesBy($this->currentUser->getUID(), \OCP\Share::SHARE_TYPE_LINK, $path, $reshares, -1, 0);
 		//TODO: Add federated shares
 
 		$shares = array_merge($userShares, $groupShares, $linkShares);
@@ -538,14 +545,6 @@ class Share20OCS {
 		return new \OC_OCS_Result($this->formatShare($share));
 	}
 
-	public function validatePermissions($permissions) {
-		if ($permissions < 0 || $permissions > \OCP\Constants::PERMISSION_ALL) {
-			return false;
-		}
-
-
-	}
-
 	/**
 	 * @param \OCP\Share\IShare $share
 	 * @return bool
@@ -557,21 +556,23 @@ class Share20OCS {
 		}
 
 		// Owner of the file and the sharer of the file can always get share
-		if ($share->getShareOwner() === $this->currentUser ||
-			$share->getSharedBy() === $this->currentUser
+		if ($share->getShareOwner() === $this->currentUser->getUID() ||
+			$share->getSharedBy() === $this->currentUser->getUID()
 		) {
 			return true;
 		}
 
 		// If the share is shared with you (or a group you are a member of)
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER &&
-			$share->getSharedWith() === $this->currentUser) {
+			$share->getSharedWith() === $this->currentUser->getUID()) {
 			return true;
 		}
 
-		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP &&
-			$share->getSharedWith()->inGroup($this->currentUser)) {
-			return true;
+		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
+			$sharedWith = $this->groupManager->get($share->getSharedWith());
+			if ($sharedWith->inGroup($this->currentUser)) {
+				return true;
+			}
 		}
 
 		return false;
diff --git a/apps/files_sharing/lib/controllers/sharecontroller.php b/apps/files_sharing/lib/controllers/sharecontroller.php
index 6ac585e275c..bbe68096b52 100644
--- a/apps/files_sharing/lib/controllers/sharecontroller.php
+++ b/apps/files_sharing/lib/controllers/sharecontroller.php
@@ -232,8 +232,8 @@ class ShareController extends Controller {
 		}
 
 		$shareTmpl = [];
-		$shareTmpl['displayName'] = $share->getShareOwner()->getDisplayName();
-		$shareTmpl['owner'] = $share->getShareOwner()->getUID();
+		$shareTmpl['displayName'] = $this->userManager->get($share->getShareOwner())->getDisplayName();
+		$shareTmpl['owner'] = $share->getShareOwner();
 		$shareTmpl['filename'] = $share->getNode()->getName();
 		$shareTmpl['directory_path'] = $share->getTarget();
 		$shareTmpl['mimetype'] = $share->getNode()->getMimetype();
@@ -320,7 +320,7 @@ class ShareController extends Controller {
 			}
 		}
 
-		$userFolder = $this->rootFolder->getUserFolder($share->getShareOwner()->getUID());
+		$userFolder = $this->rootFolder->getUserFolder($share->getShareOwner());
 		$originalSharePath = $userFolder->getRelativePath($share->getNode()->getPath());
 
 		// Single file share
@@ -330,7 +330,7 @@ class ShareController extends Controller {
 			$event->setApp('files_sharing')
 				->setType(Activity::TYPE_PUBLIC_LINKS)
 				->setSubject(Activity::SUBJECT_PUBLIC_SHARED_FILE_DOWNLOADED, [$userFolder->getRelativePath($share->getNode()->getPath())])
-				->setAffectedUser($share->getShareOwner()->getUID())
+				->setAffectedUser($share->getShareOwner())
 				->setObject('files', $share->getNode()->getId(), $userFolder->getRelativePath($share->getNode()->getPath()));
 			$this->activityManager->publish($event);
 		}
@@ -356,7 +356,7 @@ class ShareController extends Controller {
 				$event->setApp('files_sharing')
 					->setType(Activity::TYPE_PUBLIC_LINKS)
 					->setSubject(Activity::SUBJECT_PUBLIC_SHARED_FILE_DOWNLOADED, [$userFolder->getRelativePath($node->getPath())])
-					->setAffectedUser($share->getShareOwner()->getUID())
+					->setAffectedUser($share->getShareOwner())
 					->setObject('files', $node->getId(), $userFolder->getRelativePath($node->getPath()));
 				$this->activityManager->publish($event);
 			} else if (!empty($files_list)) {
@@ -369,7 +369,7 @@ class ShareController extends Controller {
 					$event = $this->activityManager->generateEvent();
 					$event->setApp('files_sharing')
 						->setType(Activity::TYPE_PUBLIC_LINKS)
-						->setAffectedUser($share->getShareOwner()->getUID())
+						->setAffectedUser($share->getShareOwner())
 						->setObject('files', $subNode->getId(), $userFolder->getRelativePath($subNode->getPath()));
 
 					if ($subNode instanceof \OCP\Files\File) {
@@ -386,7 +386,7 @@ class ShareController extends Controller {
 				$event->setApp('files_sharing')
 					->setType(Activity::TYPE_PUBLIC_LINKS)
 					->setSubject(Activity::SUBJECT_PUBLIC_SHARED_FOLDER_DOWNLOADED, [$userFolder->getRelativePath($node->getPath())])
-					->setAffectedUser($share->getShareOwner()->getUID())
+					->setAffectedUser($share->getShareOwner())
 					->setObject('files', $node->getId(), $userFolder->getRelativePath($node->getPath()));
 				$this->activityManager->publish($event);
 			}
@@ -394,7 +394,7 @@ class ShareController extends Controller {
 
 		/* FIXME: We should do this all nicely in OCP */
 		OC_Util::tearDownFS();
-		OC_Util::setupFS($share->getShareOwner()->getUID());
+		OC_Util::setupFS($share->getShareOwner());
 
 		/**
 		 * this sets a cookie to be able to recognize the start of the download
diff --git a/apps/files_sharing/tests/api/share20ocstest.php b/apps/files_sharing/tests/api/share20ocstest.php
index 1405f8f441a..a93cd5f58ce 100644
--- a/apps/files_sharing/tests/api/share20ocstest.php
+++ b/apps/files_sharing/tests/api/share20ocstest.php
@@ -55,7 +55,7 @@ class Share20OCSTest extends \Test\TestCase {
 	private $ocs;
 
 	protected function setUp() {
-		$this->shareManager = $this->getMockBuilder('OC\Share20\Manager')
+		$this->shareManager = $this->getMockBuilder('OCP\Share\IManager')
 			->disableOriginalConstructor()
 			->getMock();
 		$this->groupManager = $this->getMock('OCP\IGroupManager');
@@ -91,6 +91,10 @@ class Share20OCSTest extends \Test\TestCase {
 			->getMock();
 	}
 
+	private function newShare() {
+		return \OC::$server->getShareManager()->newShare();
+	}
+
 	public function testDeleteShareShareNotFound() {
 		$this->shareManager
 			->expects($this->once())
@@ -103,8 +107,8 @@ class Share20OCSTest extends \Test\TestCase {
 	}
 
 	public function testDeleteShare() {
-		$share = $this->getMock('OCP\Share\IShare');
-		$share->method('getSharedBy')->willReturn($this->currentUser);
+		$share = $this->newShare();
+		$share->setSharedBy($this->currentUser->getUID());
 		$this->shareManager
 			->expects($this->once())
 			->method('getShareById')
@@ -137,7 +141,7 @@ class Share20OCSTest extends \Test\TestCase {
 	public function createShare($id, $shareType, $sharedWith, $sharedBy, $shareOwner, $path, $permissions,
 								$shareTime, $expiration, $parent, $target, $mail_send, $token=null,
 								$password=null) {
-		$share = $this->getMock('OCP\Share\IShare');
+		$share = $this->getMock('\OCP\Share\IShare');
 		$share->method('getId')->willReturn($id);
 		$share->method('getShareType')->willReturn($shareType);
 		$share->method('getSharedWith')->willReturn($sharedWith);
@@ -166,21 +170,6 @@ class Share20OCSTest extends \Test\TestCase {
 	public function dataGetShare() {
 		$data = [];
 
-		$initiator = $this->getMock('OCP\IUser');
-		$initiator->method('getUID')->willReturn('initiatorId');
-		$initiator->method('getDisplayName')->willReturn('initiatorDisplay');
-
-		$owner = $this->getMock('OCP\IUser');
-		$owner->method('getUID')->willReturn('ownerId');
-		$owner->method('getDisplayName')->willReturn('ownerDisplay');
-
-		$user = $this->getMock('OCP\IUser');
-		$user->method('getUID')->willReturn('userId');
-		$user->method('getDisplayName')->willReturn('userDisplay');
-
-		$group = $this->getMock('OCP\IGroup');
-		$group->method('getGID')->willReturn('groupId');
-
 		$cache = $this->getMockBuilder('OC\Files\Cache\Cache')
 			->disableOriginalConstructor()
 			->getMock();
@@ -211,9 +200,9 @@ class Share20OCSTest extends \Test\TestCase {
 		$share = $this->createShare(
 			100,
 			\OCP\Share::SHARE_TYPE_USER,
-			$user,
-			$initiator,
-			$owner,
+			'userId',
+			'initiatorId',
+			'ownerId',
 			$file,
 			4,
 			5,
@@ -252,9 +241,9 @@ class Share20OCSTest extends \Test\TestCase {
 		$share = $this->createShare(
 			101,
 			\OCP\Share::SHARE_TYPE_GROUP,
-			$group,
-			$initiator,
-			$owner,
+			'groupId',
+			'initiatorId',
+			'ownerId',
 			$folder,
 			4,
 			5,
@@ -295,8 +284,8 @@ class Share20OCSTest extends \Test\TestCase {
 			101,
 			\OCP\Share::SHARE_TYPE_LINK,
 			null,
-			$initiator,
-			$owner,
+			'initiatorId',
+			'ownerId',
 			$folder,
 			4,
 			5,
@@ -367,29 +356,53 @@ class Share20OCSTest extends \Test\TestCase {
 			->will($this->returnArgument(0));
 
 		$this->rootFolder->method('getUserFolder')
-			->with($share->getShareOwner()->getUID())
+			->with($share->getShareOwner())
 			->willReturn($userFolder);
 
 		$this->urlGenerator
 			->method('linkToRouteAbsolute')
 			->willReturn('url');
 
+		$initiator = $this->getMock('OCP\IUser');
+		$initiator->method('getUID')->willReturn('initiatorId');
+		$initiator->method('getDisplayName')->willReturn('initiatorDisplay');
+
+		$owner = $this->getMock('OCP\IUser');
+		$owner->method('getUID')->willReturn('ownerId');
+		$owner->method('getDisplayName')->willReturn('ownerDisplay');
+
+		$user = $this->getMock('OCP\IUser');
+		$user->method('getUID')->willReturn('userId');
+		$user->method('getDisplayName')->willReturn('userDisplay');
+
+		$group = $this->getMock('OCP\IGroup');
+		$group->method('getGID')->willReturn('groupId');
+
+		$this->userManager->method('get')->will($this->returnValueMap([
+			['userId', $user],
+			['initiatorId', $initiator],
+			['ownerId', $owner],
+		]));
+		$this->groupManager->method('get')->will($this->returnValueMap([
+			['group', $group],
+		]));
+
 		$expected = new \OC_OCS_Result($result);
 		$this->assertEquals($expected->getData(), $ocs->getShare($share->getId())->getData());
 	}
 
 	public function testCanAccessShare() {
 		$share = $this->getMock('OCP\Share\IShare');
-		$share->method('getShareOwner')->willReturn($this->currentUser);
+		$share->method('getShareOwner')->willReturn($this->currentUser->getUID());
 		$this->assertTrue($this->invokePrivate($this->ocs, 'canAccessShare', [$share]));
 
 		$share = $this->getMock('OCP\Share\IShare');
-		$share->method('getSharedBy')->willReturn($this->currentUser);
+		$share->method('getSharedBy')->willReturn($this->currentUser->getUID());
 		$this->assertTrue($this->invokePrivate($this->ocs, 'canAccessShare', [$share]));
 
 		$share = $this->getMock('OCP\Share\IShare');
 		$share->method('getShareType')->willReturn(\OCP\Share::SHARE_TYPE_USER);
-		$share->method('getSharedWith')->willReturn($this->currentUser);
+		$share->method('getSharedWith')->willReturn($this->currentUser->getUID());
 		$this->assertTrue($this->invokePrivate($this->ocs, 'canAccessShare', [$share]));
 
 		$share = $this->getMock('OCP\Share\IShare');
@@ -399,16 +412,25 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = $this->getMock('OCP\Share\IShare');
 		$share->method('getShareType')->willReturn(\OCP\Share::SHARE_TYPE_GROUP);
+		$share->method('getSharedWith')->willReturn('group');
+
 		$group = $this->getMock('OCP\IGroup');
 		$group->method('inGroup')->with($this->currentUser)->willReturn(true);
-		$share->method('getSharedWith')->willReturn($group);
+		$group2 = $this->getMock('OCP\IGroup');
+		$group2->method('inGroup')->with($this->currentUser)->willReturn(false);
+
+
+		$this->groupManager->method('get')->will($this->returnValueMap([
+			['group', $group],
+			['group2', $group2],
+		]));
 		$this->assertTrue($this->invokePrivate($this->ocs, 'canAccessShare', [$share]));
 
 		$share = $this->getMock('OCP\Share\IShare');
 		$share->method('getShareType')->willReturn(\OCP\Share::SHARE_TYPE_GROUP);
-		$group = $this->getMock('OCP\IGroup');
-		$group->method('inGroup')->with($this->currentUser)->willReturn(false);
-		$share->method('getSharedWith')->willReturn($group);
+		$share->method('getSharedWith')->willReturn('group2');
+
+		$this->groupManager->method('get')->with('group2')->willReturn($group);
 		$this->assertFalse($this->invokePrivate($this->ocs, 'canAccessShare', [$share]));
 
 		$share = $this->getMock('OCP\Share\IShare');
@@ -587,7 +609,6 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$user = $this->getMock('\OCP\IUser');
 		$this->userManager->method('userExists')->with('validUser')->willReturn(true);
-		$this->userManager->method('get')->with('validUser')->willReturn($user);
 
 		$share->method('setPath')->with($path);
 		$share->method('setPermissions')
@@ -596,8 +617,8 @@ class Share20OCSTest extends \Test\TestCase {
 				~\OCP\Constants::PERMISSION_DELETE &
 				~\OCP\Constants::PERMISSION_CREATE);
 		$share->method('setShareType')->with(\OCP\Share::SHARE_TYPE_USER);
-		$share->method('setSharedWith')->with($user);
-		$share->method('setSharedBy')->with($this->currentUser);
+		$share->method('setSharedWith')->with('validUser');
+		$share->method('setSharedBy')->with('currentUser');
 
 		$expected = new \OC_OCS_Result();
 		$result = $ocs->createShare();
@@ -680,13 +701,12 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$group = $this->getMock('\OCP\IGroup');
 		$this->groupManager->method('groupExists')->with('validGroup')->willReturn(true);
-		$this->groupManager->method('get')->with('validGroup')->willReturn($group);
 
 		$share->method('setPath')->with($path);
 		$share->method('setPermissions')->with(\OCP\Constants::PERMISSION_ALL);
 		$share->method('setShareType')->with(\OCP\Share::SHARE_TYPE_GROUP);
-		$share->method('setSharedWith')->with($group);
-		$share->method('setSharedBy')->with($this->currentUser);
+		$share->method('setSharedWith')->with('validGroup');
+		$share->method('setSharedBy')->with('currentUser');
 
 		$expected = new \OC_OCS_Result();
 		$result = $ocs->createShare();
@@ -784,14 +804,12 @@ class Share20OCSTest extends \Test\TestCase {
 		$this->shareManager->method('shareApiAllowLinks')->willReturn(true);
 		$this->shareManager->method('shareApiLinkAllowPublicUpload')->willReturn(true);
 
-		$currentUser = $this->currentUser;
-
 		$this->shareManager->expects($this->once())->method('createShare')->with(
-			$this->callback(function (\OCP\Share\IShare $share) use ($path, $currentUser) {
+			$this->callback(function (\OCP\Share\IShare $share) use ($path) {
 				return $share->getNode() === $path &&
 					$share->getShareType() === \OCP\Share::SHARE_TYPE_LINK &&
 					$share->getPermissions() === \OCP\Constants::PERMISSION_READ | \OCP\Constants::PERMISSION_CREATE | \OCP\Constants::PERMISSION_DELETE &&
-					$share->getSharedBy() === $currentUser &&
+					$share->getSharedBy() === 'currentUser' &&
 					$share->getPassword() === null &&
 					$share->getExpirationDate() === null;
 			})
@@ -825,14 +843,12 @@ class Share20OCSTest extends \Test\TestCase {
 		$this->shareManager->method('shareApiAllowLinks')->willReturn(true);
 		$this->shareManager->method('shareApiLinkAllowPublicUpload')->willReturn(true);
 
-		$currentUser = $this->currentUser;
-
 		$this->shareManager->expects($this->once())->method('createShare')->with(
-			$this->callback(function (\OCP\Share\IShare $share) use ($path, $currentUser) {
+			$this->callback(function (\OCP\Share\IShare $share) use ($path) {
 				return $share->getNode() === $path &&
 				$share->getShareType() === \OCP\Share::SHARE_TYPE_LINK &&
 				$share->getPermissions() === \OCP\Constants::PERMISSION_READ &&
-				$share->getSharedBy() === $currentUser &&
+				$share->getSharedBy() === 'currentUser' &&
 				$share->getPassword() === 'password' &&
 				$share->getExpirationDate() === null;
 			})
@@ -866,17 +882,15 @@ class Share20OCSTest extends \Test\TestCase {
 		$this->shareManager->method('shareApiAllowLinks')->willReturn(true);
 		$this->shareManager->method('shareApiLinkAllowPublicUpload')->willReturn(true);
 
-		$currentUser = $this->currentUser;
-
 		$this->shareManager->expects($this->once())->method('createShare')->with(
-			$this->callback(function (\OCP\Share\IShare $share) use ($path, $currentUser) {
+			$this->callback(function (\OCP\Share\IShare $share) use ($path) {
 				$date = new \DateTime('2000-01-01');
 				$date->setTime(0,0,0);
 
 				return $share->getNode() === $path &&
 				$share->getShareType() === \OCP\Share::SHARE_TYPE_LINK &&
 				$share->getPermissions() === \OCP\Constants::PERMISSION_READ &&
-				$share->getSharedBy() === $currentUser &&
+				$share->getSharedBy() === 'currentUser' &&
 				$share->getPassword() === null &&
 				$share->getExpirationDate() == $date;
 			})
@@ -932,7 +946,7 @@ class Share20OCSTest extends \Test\TestCase {
 	public function testUpdateNoParametersLink() {
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK);
 
 		$this->shareManager->method('getShareById')->with('ocinternal:42')->willReturn($share);
@@ -947,7 +961,7 @@ class Share20OCSTest extends \Test\TestCase {
 	public function testUpdateNoParametersOther() {
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_GROUP);
 
 		$this->shareManager->method('getShareById')->with('ocinternal:42')->willReturn($share);
@@ -964,7 +978,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setPassword('password')
 			->setExpirationDate(new \DateTime())
@@ -1002,7 +1016,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setNode($folder);
 
@@ -1042,7 +1056,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setNode($folder);
 
@@ -1071,7 +1085,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setNode($folder);
 
@@ -1100,7 +1114,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setNode($file);
 
@@ -1130,7 +1144,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setPassword('password')
 			->setExpirationDate($date)
@@ -1164,7 +1178,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setPassword('password')
 			->setExpirationDate(new \DateTime())
@@ -1205,7 +1219,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setPassword('password')
 			->setExpirationDate($date)
@@ -1245,7 +1259,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setPassword('password')
 			->setExpirationDate($date)
@@ -1285,7 +1299,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setPassword('password')
 			->setExpirationDate($date)
@@ -1315,7 +1329,7 @@ class Share20OCSTest extends \Test\TestCase {
 
 		$share = \OC::$server->getShareManager()->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
-			->setSharedBy($this->currentUser)
+			->setSharedBy($this->currentUser->getUID())
 			->setShareType(\OCP\Share::SHARE_TYPE_USER)
 			->setNode($file);
 
diff --git a/apps/files_sharing/tests/controller/sharecontroller.php b/apps/files_sharing/tests/controller/sharecontroller.php
index e36ee9e4914..22e15972cd6 100644
--- a/apps/files_sharing/tests/controller/sharecontroller.php
+++ b/apps/files_sharing/tests/controller/sharecontroller.php
@@ -35,6 +35,7 @@ use OCP\AppFramework\Http\NotFoundResponse;
 use OCP\AppFramework\Http\RedirectResponse;
 use OCP\AppFramework\Http\TemplateResponse;
 use OCP\ISession;
+use OCP\IUserManager;
 use OCP\Security\ISecureRandom;
 use OCP\IURLGenerator;
 
@@ -64,6 +65,8 @@ class ShareControllerTest extends \Test\TestCase {
 	private $config;
 	/** @var  \OC\Share20\Manager | \PHPUnit_Framework_MockObject_MockObject */
 	private $shareManager;
+	/** @var IUserManager | \PHPUnit_Framework_MockObject_MockObject */
+	private $userManager;
 
 	protected function setUp() {
 		$this->appName = 'files_sharing';
@@ -73,13 +76,14 @@ class ShareControllerTest extends \Test\TestCase {
 		$this->session = $this->getMock('\OCP\ISession');
 		$this->previewManager = $this->getMock('\OCP\IPreview');
 		$this->config = $this->getMock('\OCP\IConfig');
+		$this->userManager = $this->getMock('\OCP\IUserManager');
 
 		$this->shareController = new \OCA\Files_Sharing\Controllers\ShareController(
 			$this->appName,
 			$this->getMock('\OCP\IRequest'),
 			$this->config,
 			$this->urlGenerator,
-			$this->getMock('\OCP\IUserManager'),
+			$this->userManager,
 			$this->getMock('\OCP\ILogger'),
 			$this->getMock('\OCP\Activity\IManager'),
 			$this->shareManager,
@@ -116,7 +120,7 @@ class ShareControllerTest extends \Test\TestCase {
 	}
 
 	public function testShowAuthenticateNotAuthenticated() {
-		$share = $this->getMock('\OCP\Share\IShare');
+		$share = \OC::$server->getShareManager()->newShare();
 
 		$this->shareManager
 			->expects($this->once())
@@ -130,8 +134,8 @@ class ShareControllerTest extends \Test\TestCase {
 	}
 
 	public function testShowAuthenticateAuthenticatedForDifferentShare() {
-		$share = $this->getMock('\OCP\Share\IShare');
-		$share->method('getId')->willReturn(1);
+		$share = \OC::$server->getShareManager()->newShare();
+		$share->setId(1);
 
 		$this->shareManager
 			->expects($this->once())
@@ -148,8 +152,8 @@ class ShareControllerTest extends \Test\TestCase {
 	}
 
 	public function testShowAuthenticateCorrectShare() {
-		$share = $this->getMock('\OCP\Share\IShare');
-		$share->method('getId')->willReturn(1);
+		$share = \OC::$server->getShareManager()->newShare();
+		$share->setId(1);
 
 		$this->shareManager
 			->expects($this->once())
@@ -183,8 +187,8 @@ class ShareControllerTest extends \Test\TestCase {
 	}
 
 	public function testAuthenticateValidPassword() {
-		$share = $this->getMock('\OCP\Share\IShare');
-		$share->method('getId')->willReturn(42);
+		$share = \OC::$server->getShareManager()->newShare();
+		$share->setId(42);
 
 		$this->shareManager
 			->expects($this->once())
@@ -214,8 +218,8 @@ class ShareControllerTest extends \Test\TestCase {
 	}
 
 	public function testAuthenticateInvalidPassword() {
-		$share = $this->getMock('\OCP\Share\IShare');
-		$share->method('getId')->willReturn(42);
+		$share = \OC::$server->getShareManager()->newShare();
+		$share->setId(42);
 
 		$this->shareManager
 			->expects($this->once())
@@ -252,8 +256,8 @@ class ShareControllerTest extends \Test\TestCase {
 	}
 
 	public function testShowShareNotAuthenticated() {
-		$share = $this->getMock('\OCP\Share\IShare');
-		$share->method('getPassword')->willReturn('password');
+		$share = \OC::$server->getShareManager()->newShare();
+		$share->setPassword('password');
 
 		$this->shareManager
 			->expects($this->once())
@@ -283,12 +287,12 @@ class ShareControllerTest extends \Test\TestCase {
 		$file->method('getMimetype')->willReturn('text/plain');
 		$file->method('getSize')->willReturn(33);
 
-		$share = $this->getMock('\OCP\Share\IShare');
-		$share->method('getId')->willReturn('42');
-		$share->method('getPassword')->willReturn('password');
-		$share->method('getShareOwner')->willReturn($owner);
-		$share->method('getNode')->willReturn($file);
-		$share->method('getTarget')->willReturn('/file1.txt');
+		$share = \OC::$server->getShareManager()->newShare();
+		$share->setId(42);
+		$share->setPassword('password')
+			->setShareOwner('ownerUID')
+			->setNode($file)
+			->setTarget('/file1.txt');
 
 		$this->session->method('exists')->with('public_link_authenticated')->willReturn(true);
 		$this->session->method('get')->with('public_link_authenticated')->willReturn('42');
@@ -311,6 +315,8 @@ class ShareControllerTest extends \Test\TestCase {
 			->with('token')
 			->willReturn($share);
 
+		$this->userManager->method('get')->with('ownerUID')->willReturn($owner);
+
 		$response = $this->shareController->showShare('token');
 		$sharedTmplParams = array(
 			'displayName' => 'ownerDisplay',
diff --git a/lib/private/server.php b/lib/private/server.php
index d3dbcba86ba..69406c2203f 100644
--- a/lib/private/server.php
+++ b/lib/private/server.php
@@ -617,7 +617,8 @@ class Server extends ServerContainer implements IServerContainer {
 				$c->getMountManager(),
 				$c->getGroupManager(),
 				$c->getL10N('core'),
-				$factory
+				$factory,
+				$c->getUserManager()
 			);
 
 			return $manager;
diff --git a/lib/private/share20/defaultshareprovider.php b/lib/private/share20/defaultshareprovider.php
index 7b78be2b61d..38d1dae316d 100644
--- a/lib/private/share20/defaultshareprovider.php
+++ b/lib/private/share20/defaultshareprovider.php
@@ -29,7 +29,6 @@ use OC\Share20\Exception\BackendError;
 use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\Files\NotFoundException;
 use OCP\IGroup;
-use OCP\IUser;
 use OCP\IGroupManager;
 use OCP\IUserManager;
 use OCP\Files\IRootFolder;
@@ -102,14 +101,10 @@ class DefaultShareProvider implements IShareProvider {
 
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER) {
 			//Set the UID of the user we share with
-			/** @var IUser $sharedWith */
-			$sharedWith = $share->getSharedWith();
-			$qb->setValue('share_with', $qb->createNamedParameter($sharedWith->getUID()));
+			$qb->setValue('share_with', $qb->createNamedParameter($share->getSharedWith()));
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
 			//Set the GID of the group we share with
-			/** @var IGroup $sharedWith */
-			$sharedWith = $share->getSharedWith();
-			$qb->setValue('share_with', $qb->createNamedParameter($sharedWith->getGID()));
+			$qb->setValue('share_with', $qb->createNamedParameter($share->getSharedWith()));
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_LINK) {
 			//Set the token of the share
 			$qb->setValue('token', $qb->createNamedParameter($share->getToken()));
@@ -143,10 +138,10 @@ class DefaultShareProvider implements IShareProvider {
 		$qb->setValue('permissions', $qb->createNamedParameter($share->getPermissions()));
 
 		// Set who created this share
-		$qb->setValue('uid_initiator', $qb->createNamedParameter($share->getSharedBy()->getUID()));
+		$qb->setValue('uid_initiator', $qb->createNamedParameter($share->getSharedBy()));
 
 		// Set who is the owner of this file/folder (and this the owner of the share)
-		$qb->setValue('uid_owner', $qb->createNamedParameter($share->getShareOwner()->getUID()));
+		$qb->setValue('uid_owner', $qb->createNamedParameter($share->getShareOwner()));
 
 		// Set the file target
 		$qb->setValue('file_target', $qb->createNamedParameter($share->getTarget()));
@@ -192,9 +187,9 @@ class DefaultShareProvider implements IShareProvider {
 			$qb = $this->dbConn->getQueryBuilder();
 			$qb->update('share')
 				->where($qb->expr()->eq('id', $qb->createNamedParameter($share->getId())))
-				->set('share_with', $qb->createNamedParameter($share->getSharedWith()->getUID()))
-				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()->getUID()))
-				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()->getUID()))
+				->set('share_with', $qb->createNamedParameter($share->getSharedWith()))
+				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()))
+				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()))
 				->set('permissions', $qb->createNamedParameter($share->getPermissions()))
 				->set('item_source', $qb->createNamedParameter($share->getNode()->getId()))
 				->set('file_source', $qb->createNamedParameter($share->getNode()->getId()))
@@ -203,8 +198,8 @@ class DefaultShareProvider implements IShareProvider {
 			$qb = $this->dbConn->getQueryBuilder();
 			$qb->update('share')
 				->where($qb->expr()->eq('id', $qb->createNamedParameter($share->getId())))
-				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()->getUID()))
-				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()->getUID()))
+				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()))
+				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()))
 				->set('permissions', $qb->createNamedParameter($share->getPermissions()))
 				->set('item_source', $qb->createNamedParameter($share->getNode()->getId()))
 				->set('file_source', $qb->createNamedParameter($share->getNode()->getId()))
@@ -216,8 +211,8 @@ class DefaultShareProvider implements IShareProvider {
 			$qb = $this->dbConn->getQueryBuilder();
 			$qb->update('share')
 				->where($qb->expr()->eq('parent', $qb->createNamedParameter($share->getId())))
-				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()->getUID()))
-				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()->getUID()))
+				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()))
+				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()))
 				->set('item_source', $qb->createNamedParameter($share->getNode()->getId()))
 				->set('file_source', $qb->createNamedParameter($share->getNode()->getId()))
 				->execute();
@@ -237,8 +232,8 @@ class DefaultShareProvider implements IShareProvider {
 			$qb->update('share')
 				->where($qb->expr()->eq('id', $qb->createNamedParameter($share->getId())))
 				->set('share_with', $qb->createNamedParameter($share->getPassword()))
-				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()->getUID()))
-				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()->getUID()))
+				->set('uid_owner', $qb->createNamedParameter($share->getShareOwner()))
+				->set('uid_initiator', $qb->createNamedParameter($share->getSharedBy()))
 				->set('permissions', $qb->createNamedParameter($share->getPermissions()))
 				->set('item_source', $qb->createNamedParameter($share->getNode()->getId()))
 				->set('file_source', $qb->createNamedParameter($share->getNode()->getId()))
@@ -255,7 +250,7 @@ class DefaultShareProvider implements IShareProvider {
 	 * FIXME: remove once https://github.com/owncloud/core/pull/21660 is in
 	 *
 	 * @param \OCP\Share\IShare $parent
-	 * @return IShare[]
+	 * @return \OCP\Share\IShare[]
 	 */
 	public function getChildren(\OCP\Share\IShare $parent) {
 		$children = [];
@@ -311,17 +306,17 @@ class DefaultShareProvider implements IShareProvider {
 	 * this means we need a special entry in the share db.
 	 *
 	 * @param \OCP\Share\IShare $share
-	 * @param IUser $recipient
+	 * @param string $recipient UserId of recipient
 	 * @throws BackendError
 	 * @throws ProviderException
 	 */
-	public function deleteFromSelf(\OCP\Share\IShare $share, IUser $recipient) {
+	public function deleteFromSelf(\OCP\Share\IShare $share, $recipient) {
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
 
-			/** @var IGroup $group */
-			$group = $share->getSharedWith();
+			$group = $this->groupManager->get($share->getSharedWith());
+			$user = $this->userManager->get($recipient);
 
-			if (!$group->inGroup($recipient)) {
+			if (!$group->inGroup($user)) {
 				throw new ProviderException('Recipient not in receiving group');
 			}
 
@@ -330,7 +325,7 @@ class DefaultShareProvider implements IShareProvider {
 			$stmt = $qb->select('*')
 				->from('share')
 				->where($qb->expr()->eq('share_type', $qb->createNamedParameter(self::SHARE_TYPE_USERGROUP)))
-				->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($recipient->getUID())))
+				->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($recipient)))
 				->andWhere($qb->expr()->eq('parent', $qb->createNamedParameter($share->getId())))
 				->execute();
 
@@ -349,9 +344,9 @@ class DefaultShareProvider implements IShareProvider {
 				$qb->insert('share')
 					->values([
 						'share_type' => $qb->createNamedParameter(self::SHARE_TYPE_USERGROUP),
-						'share_with' => $qb->createNamedParameter($recipient->getUID()),
-						'uid_owner' => $qb->createNamedParameter($share->getShareOwner()->getUID()),
-						'uid_initiator' => $qb->createNamedParameter($share->getSharedBy()->getUID()),
+						'share_with' => $qb->createNamedParameter($recipient),
+						'uid_owner' => $qb->createNamedParameter($share->getShareOwner()),
+						'uid_initiator' => $qb->createNamedParameter($share->getSharedBy()),
 						'parent' => $qb->createNamedParameter($share->getId()),
 						'item_type' => $qb->createNamedParameter($type),
 						'item_source' => $qb->createNamedParameter($share->getNode()->getId()),
@@ -387,7 +382,7 @@ class DefaultShareProvider implements IShareProvider {
 	/**
 	 * @inheritdoc
 	 */
-	public function move(\OCP\Share\IShare $share, IUser $recipient) {
+	public function move(\OCP\Share\IShare $share, $recipient) {
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER) {
 			// Just update the target
 			$qb = $this->dbConn->getQueryBuilder();
@@ -403,7 +398,7 @@ class DefaultShareProvider implements IShareProvider {
 			$stmt = $qb->select('id')
 				->from('share')
 				->where($qb->expr()->eq('share_type', $qb->createNamedParameter(self::SHARE_TYPE_USERGROUP)))
-				->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($recipient->getUID())))
+				->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($recipient)))
 				->andWhere($qb->expr()->eq('parent', $qb->createNamedParameter($share->getId())))
 				->setMaxResults(1)
 				->execute();
@@ -417,9 +412,9 @@ class DefaultShareProvider implements IShareProvider {
 				$qb->insert('share')
 					->values([
 						'share_type' => $qb->createNamedParameter(self::SHARE_TYPE_USERGROUP),
-						'share_with' => $qb->createNamedParameter($recipient->getUID()),
-						'uid_owner' => $qb->createNamedParameter($share->getShareOwner()->getUID()),
-						'uid_initiator' => $qb->createNamedParameter($share->getSharedBy()->getUID()),
+						'share_with' => $qb->createNamedParameter($recipient),
+						'uid_owner' => $qb->createNamedParameter($share->getShareOwner()),
+						'uid_initiator' => $qb->createNamedParameter($share->getSharedBy()),
 						'parent' => $qb->createNamedParameter($share->getId()),
 						'item_type' => $qb->createNamedParameter($share->getNode() instanceof File ? 'file' : 'folder'),
 						'item_source' => $qb->createNamedParameter($share->getNode()->getId()),
@@ -444,7 +439,7 @@ class DefaultShareProvider implements IShareProvider {
 	/**
 	 * Get all shares by the given user. Sharetype and path can be used to filter.
 	 *
-	 * @param IUser $user
+	 * @param string $userId
 	 * @param int $shareType
 	 * @param \OCP\Files\File|\OCP\Files\Folder $node
 	 * @param bool $reshares Also get the shares where $user is the owner instead of just the shares where $user is the initiator
@@ -452,7 +447,7 @@ class DefaultShareProvider implements IShareProvider {
 	 * @param int $offset
 	 * @return Share[]
 	 */
-	public function getSharesBy(IUser $user, $shareType, $node, $reshares, $limit, $offset) {
+	public function getSharesBy($userId, $shareType, $node, $reshares, $limit, $offset) {
 		$qb = $this->dbConn->getQueryBuilder();
 		$qb->select('*')
 			->from('share');
@@ -465,21 +460,21 @@ class DefaultShareProvider implements IShareProvider {
 		if ($reshares === false) {
 			//Special case for old shares created via the web UI
 			$or1 = $qb->expr()->andX(
-				$qb->expr()->eq('uid_owner', $qb->createNamedParameter($user->getUID())),
+				$qb->expr()->eq('uid_owner', $qb->createNamedParameter($userId)),
 				$qb->expr()->isNull('uid_initiator')
 			);
 
 			$qb->andWhere(
 				$qb->expr()->orX(
-					$qb->expr()->eq('uid_initiator', $qb->createNamedParameter($user->getUID())),
+					$qb->expr()->eq('uid_initiator', $qb->createNamedParameter($userId)),
 					$or1
 				)
 			);
 		} else {
 			$qb->andWhere(
 				$qb->expr()->orX(
-					$qb->expr()->eq('uid_owner', $qb->createNamedParameter($user->getUID())),
-					$qb->expr()->eq('uid_initiator', $qb->createNamedParameter($user->getUID()))
+					$qb->expr()->eq('uid_owner', $qb->createNamedParameter($userId)),
+					$qb->expr()->eq('uid_initiator', $qb->createNamedParameter($userId))
 				)
 			);
 		}
@@ -508,7 +503,7 @@ class DefaultShareProvider implements IShareProvider {
 	/**
 	 * @inheritdoc
 	 */
-	public function getShareById($id, $recipient = null) {
+	public function getShareById($id, $recipientId = null) {
 		$qb = $this->dbConn->getQueryBuilder();
 
 		$qb->select('*')
@@ -540,8 +535,8 @@ class DefaultShareProvider implements IShareProvider {
 		}
 
 		// If the recipient is set for a group share resolve to that user
-		if ($recipient !== null && $share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
-			$share = $this->resolveGroupShare($share, $recipient);
+		if ($recipientId !== null && $share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
+			$share = $this->resolveGroupShare($share, $recipientId);
 		}
 
 		return $share;
@@ -551,7 +546,7 @@ class DefaultShareProvider implements IShareProvider {
 	 * Get shares for a given path
 	 *
 	 * @param \OCP\Files\Node $path
-	 * @return IShare[]
+	 * @return \OCP\Share\IShare[]
 	 */
 	public function getSharesByPath(Node $path) {
 		$qb = $this->dbConn->getQueryBuilder();
@@ -578,7 +573,7 @@ class DefaultShareProvider implements IShareProvider {
 	/**
 	 * @inheritdoc
 	 */
-	public function getSharedWith(IUser $user, $shareType, $node, $limit, $offset) {
+	public function getSharedWith($userId, $shareType, $node, $limit, $offset) {
 		/** @var Share[] $shares */
 		$shares = [];
 
@@ -598,7 +593,7 @@ class DefaultShareProvider implements IShareProvider {
 			$qb->setFirstResult($offset);
 
 			$qb->where($qb->expr()->eq('share_type', $qb->createNamedParameter(\OCP\Share::SHARE_TYPE_USER)));
-			$qb->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($user->getUID())));
+			$qb->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($userId)));
 
 			// Filter by node if provided
 			if ($node !== null) {
@@ -613,6 +608,7 @@ class DefaultShareProvider implements IShareProvider {
 			$cursor->closeCursor();
 
 		} else if ($shareType === \OCP\Share::SHARE_TYPE_GROUP) {
+			$user = $this->userManager->get($userId);
 			$allGroups = $this->groupManager->getUserGroups($user);
 
 			/** @var Share[] $shares2 */
@@ -666,7 +662,7 @@ class DefaultShareProvider implements IShareProvider {
  			 * TODO: Optmize this!
  			 */
 			foreach($shares2 as $share) {
-				$shares[] = $this->resolveGroupShare($share, $user);
+				$shares[] = $this->resolveGroupShare($share, $userId);
 			}
 		} else {
 			throw new BackendError('Invalid backend');
@@ -680,7 +676,7 @@ class DefaultShareProvider implements IShareProvider {
 	 * Get a share by token
 	 *
 	 * @param string $token
-	 * @return IShare
+	 * @return \OCP\Share\IShare
 	 * @throws ShareNotFound
 	 */
 	public function getShareByToken($token) {
@@ -727,17 +723,9 @@ class DefaultShareProvider implements IShareProvider {
 		$share->setShareTime($shareTime);
 
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER) {
-			$sharedWith = $this->userManager->get($data['share_with']);
-			if ($sharedWith === null) {
-				throw new InvalidShare();
-			}
-			$share->setSharedWith($sharedWith);
+			$share->setSharedWith($data['share_with']);
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
-			$sharedWith = $this->groupManager->get($data['share_with']);
-			if ($sharedWith === null) {
-				throw new InvalidShare();
-			}
-			$share->setSharedWith($sharedWith);
+			$share->setSharedWith($data['share_with']);
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_LINK) {
 			$share->setPassword($data['share_with']);
 			$share->setToken($data['token']);
@@ -745,24 +733,15 @@ class DefaultShareProvider implements IShareProvider {
 
 		if ($data['uid_initiator'] === null) {
 			//OLD SHARE
-			$sharedBy = $this->userManager->get($data['uid_owner']);
-			if ($sharedBy === null) {
-				throw new InvalidShare();
-			}
-			$share->setSharedBy($sharedBy);
+			$share->setSharedBy($data['uid_owner']);
 			$path = $this->getNode($share->getSharedBy(), (int)$data['file_source']);
 
 			$owner = $path->getOwner();
-			$share->setShareOwner($owner);
+			$share->setShareOwner($owner->getUID());
 		} else {
 			//New share!
-			$sharedBy = $this->userManager->get($data['uid_initiator']);
-			$shareOwner = $this->userManager->get($data['uid_owner']);
-			if ($sharedBy === null || $shareOwner === null) {
-				throw new InvalidShare();
-			}
-			$share->setSharedBy($sharedBy);
-			$share->setShareOwner($shareOwner);
+			$share->setSharedBy($data['uid_initiator']);
+			$share->setShareOwner($data['uid_owner']);
 		}
 
 		$path = $this->getNode($share->getShareOwner(), (int)$data['file_source']);
@@ -781,14 +760,14 @@ class DefaultShareProvider implements IShareProvider {
 	/**
 	 * Get the node with file $id for $user
 	 *
-	 * @param IUser $user
+	 * @param string $user The userId
 	 * @param int $id
 	 * @return \OCP\Files\File|\OCP\Files\Folder
 	 * @throws InvalidShare
 	 */
-	private function getNode(IUser $user, $id) {
+	private function getNode($user, $id) {
 		try {
-			$userFolder = $this->rootFolder->getUserFolder($user->getUID());
+			$userFolder = $this->rootFolder->getUserFolder($user);
 		} catch (NotFoundException $e) {
 			throw new InvalidShare();
 		}
@@ -806,18 +785,18 @@ class DefaultShareProvider implements IShareProvider {
 	 * Resolve a group share to a user specific share
 	 * Thus if the user moved their group share make sure this is properly reflected here.
 	 *
-	 * @param Share $share
-	 * @param IUser $user
+	 * @param \OCP\Share\IShare $share
+	 * @param string $userId
 	 * @return Share Returns the updated share if one was found else return the original share.
 	 */
-	private function resolveGroupShare(Share $share, IUser $user) {
+	private function resolveGroupShare(\OCP\Share\IShare $share, $userId) {
 		$qb = $this->dbConn->getQueryBuilder();
 
 		$stmt = $qb->select('*')
 			->from('share')
 			->where($qb->expr()->eq('parent', $qb->createNamedParameter($share->getId())))
 			->andWhere($qb->expr()->eq('share_type', $qb->createNamedParameter(self::SHARE_TYPE_USERGROUP)))
-			->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($user->getUID())))
+			->andWhere($qb->expr()->eq('share_with', $qb->createNamedParameter($userId)))
 			->setMaxResults(1)
 			->execute();
 
diff --git a/lib/private/share20/manager.php b/lib/private/share20/manager.php
index 520b5a53762..db42f76d7a2 100644
--- a/lib/private/share20/manager.php
+++ b/lib/private/share20/manager.php
@@ -21,7 +21,7 @@
 
 namespace OC\Share20;
 
-use OCP\Files\Node;
+use OCP\IUserManager;
 use OCP\Share\IManager;
 use OCP\Share\IProviderFactory;
 use OC\Share20\Exception\BackendError;
@@ -34,7 +34,6 @@ use OCP\Files\Mount\IMountManager;
 use OCP\IGroupManager;
 use OCP\Files\File;
 use OCP\Files\Folder;
-use OCP\IUser;
 
 use OCP\Share\Exceptions\ShareNotFound;
 use OCP\Share\Exceptions\GenericShareException;
@@ -68,6 +67,9 @@ class Manager implements IManager {
 	/** @var IL10N */
 	private $l;
 
+	/** @var IUserManager */
+	private $userManager;
+
 	/**
 	 * Manager constructor.
 	 *
@@ -79,6 +81,7 @@ class Manager implements IManager {
 	 * @param IGroupManager $groupManager
 	 * @param IL10N $l
 	 * @param IProviderFactory $factory
+	 * @param IUserManager $userManager
 	 */
 	public function __construct(
 			ILogger $logger,
@@ -88,7 +91,8 @@ class Manager implements IManager {
 			IMountManager $mountManager,
 			IGroupManager $groupManager,
 			IL10N $l,
-			IProviderFactory $factory
+			IProviderFactory $factory,
+			IUserManager $userManager
 	) {
 		$this->logger = $logger;
 		$this->config = $config;
@@ -98,6 +102,7 @@ class Manager implements IManager {
 		$this->groupManager = $groupManager;
 		$this->l = $l;
 		$this->factory = $factory;
+		$this->userManager = $userManager;
 	}
 
 	/**
@@ -150,13 +155,13 @@ class Manager implements IManager {
 	protected function generalCreateChecks(\OCP\Share\IShare $share) {
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER) {
 			// We expect a valid user as sharedWith for user shares
-			if (!($share->getSharedWith() instanceof \OCP\IUser)) {
-				throw new \InvalidArgumentException('SharedWith should be an IUser');
+			if (!$this->userManager->userExists($share->getSharedWith())) {
+				throw new \InvalidArgumentException('SharedWith is not a valid user');
 			}
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
 			// We expect a valid group as sharedWith for group shares
-			if (!($share->getSharedWith() instanceof \OCP\IGroup)) {
-				throw new \InvalidArgumentException('SharedWith should be an IGroup');
+			if (!$this->groupManager->groupExists($share->getSharedWith())) {
+				throw new \InvalidArgumentException('SharedWith is not a valid group');
 			}
 		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_LINK) {
 			if ($share->getSharedWith() !== null) {
@@ -173,7 +178,8 @@ class Manager implements IManager {
 		}
 
 		// Cannot share with yourself
-		if ($share->getSharedWith() === $share->getSharedBy()) {
+		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER &&
+			$share->getSharedWith() === $share->getSharedBy()) {
 			throw new \InvalidArgumentException('Can\'t share with yourself');
 		}
 
@@ -215,7 +221,7 @@ class Manager implements IManager {
 	 * Validate if the expiration date fits the system settings
 	 *
 	 * @param \OCP\Share\IShare $share The share to validate the expiration date of
-	 * @return \DateTime|null The expiration date or null if $expireDate was null and it is not required
+	 * @return \OCP\Share\IShare The expiration date or null if $expireDate was null and it is not required
 	 * @throws GenericShareException
 	 * @throws \InvalidArgumentException
 	 * @throws \Exception
@@ -285,10 +291,12 @@ class Manager implements IManager {
 	protected function userCreateChecks(\OCP\Share\IShare $share) {
 		// Check if we can share with group members only
 		if ($this->shareWithGroupMembersOnly()) {
+			$sharedBy = $this->userManager->get($share->getSharedBy());
+			$sharedWith = $this->userManager->get($share->getSharedWith());
 			// Verify we can share with this user
 			$groups = array_intersect(
-					$this->groupManager->getUserGroupIds($share->getSharedBy()),
-					$this->groupManager->getUserGroupIds($share->getSharedWith())
+					$this->groupManager->getUserGroupIds($sharedBy),
+					$this->groupManager->getUserGroupIds($sharedWith)
 			);
 			if (empty($groups)) {
 				throw new \Exception('Only sharing with group members is allowed');
@@ -314,10 +322,13 @@ class Manager implements IManager {
 			}
 
 			// The share is already shared with this user via a group share
-			if ($existingShare->getShareType() === \OCP\Share::SHARE_TYPE_GROUP &&
-					$existingShare->getSharedWith()->inGroup($share->getSharedWith()) &&
-					$existingShare->getShareOwner() !== $share->getShareOwner()) {
-				throw new \Exception('Path already shared with this user');
+			if ($existingShare->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
+				$group = $this->groupManager->get($existingShare->getSharedWith());
+				$user = $this->userManager->get($share->getSharedWith());
+
+				if ($group->inGroup($user) && $existingShare->getShareOwner() !== $share->getShareOwner()) {
+					throw new \Exception('Path already shared with this user');
+				}
 			}
 		}
 	}
@@ -331,7 +342,9 @@ class Manager implements IManager {
 	protected function groupCreateChecks(\OCP\Share\IShare $share) {
 		// Verify if the user can share with this group
 		if ($this->shareWithGroupMembersOnly()) {
-			if (!$share->getSharedWith()->inGroup($share->getSharedBy())) {
+			$sharedBy = $this->userManager->get($share->getSharedBy());
+			$sharedWith = $this->groupManager->get($share->getSharedWith());
+			if (!$sharedWith->inGroup($sharedBy)) {
 				throw new \Exception('Only sharing within your own groups is allowed');
 			}
 		}
@@ -468,10 +481,11 @@ class Manager implements IManager {
 		$this->pathCreateChecks($share->getNode());
 
 		// On creation of a share the owner is always the owner of the path
-		$share->setShareOwner($share->getNode()->getOwner());
+		$share->setShareOwner($share->getNode()->getOwner()->getUID());
 
 		// Cannot share with the owner
-		if ($share->getSharedWith() === $share->getShareOwner()) {
+		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER &&
+			$share->getSharedWith() === $share->getShareOwner()) {
 			throw new \InvalidArgumentException('Can\'t share with the share owner');
 		}
 
@@ -480,16 +494,6 @@ class Manager implements IManager {
 		$target = \OC\Files\Filesystem::normalizePath($target);
 		$share->setTarget($target);
 
-		//Get sharewith for hooks
-		$sharedWith = null;
-		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER) {
-			$sharedWith = $share->getSharedWith()->getUID();
-		} else if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
-			$sharedWith = $share->getSharedWith()->getGID();
-		} else {
-			$sharedWith = $share->getSharedWith();
-		}
-
 		// Pre share hook
 		$run = true;
 		$error = '';
@@ -497,13 +501,13 @@ class Manager implements IManager {
 			'itemType' => $share->getNode() instanceof \OCP\Files\File ? 'file' : 'folder',
 			'itemSource' => $share->getNode()->getId(),
 			'shareType' => $share->getShareType(),
-			'uidOwner' => $share->getSharedBy()->getUID(),
+			'uidOwner' => $share->getSharedBy(),
 			'permissions' => $share->getPermissions(),
 			'fileSource' => $share->getNode()->getId(),
 			'expiration' => $share->getExpirationDate(),
 			'token' => $share->getToken(),
 			'itemTarget' => $share->getTarget(),
-			'shareWith' => $sharedWith,
+			'shareWith' => $share->getSharedWith(),
 			'run' => &$run,
 			'error' => &$error,
 		];
@@ -521,13 +525,13 @@ class Manager implements IManager {
 			'itemType' => $share->getNode() instanceof \OCP\Files\File ? 'file' : 'folder',
 			'itemSource' => $share->getNode()->getId(),
 			'shareType' => $share->getShareType(),
-			'uidOwner' => $share->getSharedBy()->getUID(),
+			'uidOwner' => $share->getSharedBy(),
 			'permissions' => $share->getPermissions(),
 			'fileSource' => $share->getNode()->getId(),
 			'expiration' => $share->getExpirationDate(),
 			'token' => $share->getToken(),
 			'id' => $share->getId(),
-			'shareWith' => $sharedWith,
+			'shareWith' => $share->getSharedWith(),
 			'itemTarget' => $share->getTarget(),
 			'fileTarget' => $share->getTarget(),
 		];
@@ -542,6 +546,7 @@ class Manager implements IManager {
 	 *
 	 * @param \OCP\Share\IShare $share
 	 * @return \OCP\Share\IShare The share object
+	 * @throws \InvalidArgumentException
 	 */
 	public function updateShare(\OCP\Share\IShare $share) {
 		$expirationDateUpdated = false;
@@ -564,7 +569,8 @@ class Manager implements IManager {
 		}
 
 		// Cannot share with the owner
-		if ($share->getSharedWith() === $share->getShareOwner()) {
+		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER &&
+			$share->getSharedWith() === $share->getShareOwner()) {
 			throw new \InvalidArgumentException('Can\'t share with the share owner');
 		}
 
@@ -606,7 +612,7 @@ class Manager implements IManager {
 				'itemType' => $share->getNode() instanceof \OCP\Files\File ? 'file' : 'folder',
 				'itemSource' => $share->getNode()->getId(),
 				'date' => $share->getExpirationDate(),
-				'uidOwner' => $share->getSharedBy()->getUID(),
+				'uidOwner' => $share->getSharedBy(),
 			]);
 		}
 
@@ -651,9 +657,9 @@ class Manager implements IManager {
 			$shareType = $share->getShareType();
 			$sharedWith = '';
 			if ($shareType === \OCP\Share::SHARE_TYPE_USER) {
-				$sharedWith = $share->getSharedWith()->getUID();
+				$sharedWith = $share->getSharedWith();
 			} else if ($shareType === \OCP\Share::SHARE_TYPE_GROUP) {
-				$sharedWith = $share->getSharedWith()->getGID();
+				$sharedWith = $share->getSharedWith();
 			} else if ($shareType === \OCP\Share::SHARE_TYPE_REMOTE) {
 				$sharedWith = $share->getSharedWith();
 			}
@@ -665,7 +671,7 @@ class Manager implements IManager {
 				'shareType'  => $shareType,
 				'shareWith'  => $sharedWith,
 				'itemparent' => $share->getParent(),
-				'uidOwner'   => $share->getSharedBy()->getUID(),
+				'uidOwner'   => $share->getSharedBy(),
 				'fileSource' => $share->getNode()->getId(),
 				'fileTarget' => $share->getTarget()
 			];
@@ -706,38 +712,45 @@ class Manager implements IManager {
 	 * handle this.
 	 *
 	 * @param \OCP\Share\IShare $share
-	 * @param IUser $recipient
+	 * @param string $recipientId
 	 */
-	public function deleteFromSelf(\OCP\Share\IShare $share, IUser $recipient) {
-		list($providerId, $id) = $this->splitFullId($share->getId());
+	public function deleteFromSelf(\OCP\Share\IShare $share, $recipientId) {
+		list($providerId, ) = $this->splitFullId($share->getId());
 		$provider = $this->factory->getProvider($providerId);
 
-		$provider->deleteFromSelf($share, $recipient);
+		$provider->deleteFromSelf($share, $recipientId);
 	}
 
 	/**
 	 * @inheritdoc
 	 */
-	public function moveShare(\OCP\Share\IShare $share, IUser $recipient) {
+	public function moveShare(\OCP\Share\IShare $share, $recipientId) {
 		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_LINK) {
 			throw new \InvalidArgumentException('Can\'t change target of link share');
 		}
 
-		if (($share->getShareType() === \OCP\Share::SHARE_TYPE_USER && $share->getSharedWith() !== $recipient) ||
-			($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP && !$share->getSharedWith()->inGroup($recipient))) {
+		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_USER && $share->getSharedWith() !== $recipientId) {
 			throw new \InvalidArgumentException('Invalid recipient');
 		}
 
+		if ($share->getShareType() === \OCP\Share::SHARE_TYPE_GROUP) {
+			$sharedWith = $this->groupManager->get($share->getSharedWith());
+			$recipient = $this->userManager->get($recipientId);
+			if (!$sharedWith->inGroup($recipient)) {
+				throw new \InvalidArgumentException('Invalid recipient');
+			}
+		}
+
 		list($providerId, ) = $this->splitFullId($share->getId());
 		$provider = $this->factory->getProvider($providerId);
 
-		$provider->move($share, $recipient);
+		$provider->move($share, $recipientId);
 	}
 
 	/**
 	 * Get shares shared by (initiated) by the provided user.
 	 *
-	 * @param IUser $user
+	 * @param string $userId
 	 * @param int $shareType
 	 * @param \OCP\Files\File|\OCP\Files\Folder $path
 	 * @param bool $reshares
@@ -745,7 +758,7 @@ class Manager implements IManager {
 	 * @param int $offset
 	 * @return \OCP\Share\IShare[]
 	 */
-	public function getSharesBy(IUser $user, $shareType, $path = null, $reshares = false, $limit = 50, $offset = 0) {
+	public function getSharesBy($userId, $shareType, $path = null, $reshares = false, $limit = 50, $offset = 0) {
 		if ($path !== null &&
 				!($path instanceof \OCP\Files\File) &&
 				!($path instanceof \OCP\Files\Folder)) {
@@ -754,16 +767,16 @@ class Manager implements IManager {
 
 		$provider = $this->factory->getProviderForType($shareType);
 
-		return $provider->getSharesBy($user, $shareType, $path, $reshares, $limit, $offset);
+		return $provider->getSharesBy($userId, $shareType, $path, $reshares, $limit, $offset);
 	}
 
 	/**
 	 * @inheritdoc
 	 */
-	public function getSharedWith(IUser $user, $shareType, $node = null, $limit = 50, $offset = 0) {
+	public function getSharedWith($userId, $shareType, $node = null, $limit = 50, $offset = 0) {
 		$provider = $this->factory->getProviderForType($shareType);
 
-		return $provider->getSharedWith($user, $shareType, $node, $limit, $offset);
+		return $provider->getSharedWith($userId, $shareType, $node, $limit, $offset);
 	}
 
 	/**
@@ -955,10 +968,10 @@ class Manager implements IManager {
 	 *
 	 * TODO: Deprecate fuction from OC_Util
 	 *
-	 * @param IUser $user
+	 * @param string $userId
 	 * @return bool
 	 */
-	public function sharingDisabledForUser(IUser $user) {
+	public function sharingDisabledForUser($userId) {
 		if ($this->config->getAppValue('core', 'shareapi_exclude_groups', 'no') === 'yes') {
 			$groupsList = $this->config->getAppValue('core', 'shareapi_exclude_groups_list', '');
 			$excludedGroups = json_decode($groupsList);
@@ -967,6 +980,7 @@ class Manager implements IManager {
 				$newValue = json_encode($excludedGroups);
 				$this->config->setAppValue('core', 'shareapi_exclude_groups_list', $newValue);
 			}
+			$user = $this->userManager->get($userId);
 			$usersGroups = $this->groupManager->getUserGroupIds($user);
 			if (!empty($usersGroups)) {
 				$remainingGroups = array_diff($usersGroups, $excludedGroups);
diff --git a/lib/private/share20/share.php b/lib/private/share20/share.php
index f9cba10a07a..db91ad4a91d 100644
--- a/lib/private/share20/share.php
+++ b/lib/private/share20/share.php
@@ -121,6 +121,9 @@ class Share implements \OCP\Share\IShare {
 	 * @inheritdoc
 	 */
 	public function setSharedWith($sharedWith) {
+		if (!is_string($sharedWith)) {
+			throw new \InvalidArgumentException();
+		}
 		$this->sharedWith = $sharedWith;
 		return $this;
 	}
@@ -170,6 +173,9 @@ class Share implements \OCP\Share\IShare {
 	 * @inheritdoc
 	 */
 	public function setSharedBy($sharedBy) {
+		if (!is_string($sharedBy)) {
+			throw new \InvalidArgumentException();
+		}
 		//TODO checks
 		$this->sharedBy = $sharedBy;
 
@@ -188,6 +194,9 @@ class Share implements \OCP\Share\IShare {
 	 * @inheritdoc
 	 */
 	public function setShareOwner($shareOwner) {
+		if (!is_string($shareOwner)) {
+			throw new \InvalidArgumentException();
+		}
 		//TODO checks
 
 		$this->shareOwner = $shareOwner;
diff --git a/lib/public/share/imanager.php b/lib/public/share/imanager.php
index 15b9f34764e..4d79f97c31a 100644
--- a/lib/public/share/imanager.php
+++ b/lib/public/share/imanager.php
@@ -69,27 +69,27 @@ interface IManager {
 	 * handle this.
 	 *
 	 * @param IShare $share
-	 * @param IUser $recipient
+	 * @param string $recipientId
 	 * @since 9.0.0
 	 */
-	public function deleteFromSelf(IShare $share, IUser $recipient);
+	public function deleteFromSelf(IShare $share, $recipientId);
 
 	/**
 	 * Move the share as a recipient of the share.
 	 * This is updating the share target. So where the recipient has the share mounted.
 	 *
 	 * @param IShare $share
-	 * @param IUser $recipient
+	 * @param string $recipientId
 	 * @return IShare
 	 * @throws \InvalidArgumentException If $share is a link share or the $recipient does not match
 	 * @since 9.0.0
 	 */
-	public function moveShare(IShare $share, IUser $recipient);
+	public function moveShare(IShare $share, $recipientId);
 
 	/**
 	 * Get shares shared by (initiated) by the provided user.
 	 *
-	 * @param IUser $user
+	 * @param string $userId
 	 * @param int $shareType
 	 * @param \OCP\Files\File|\OCP\Files\Folder $path
 	 * @param bool $reshares
@@ -98,13 +98,13 @@ interface IManager {
 	 * @return IShare[]
 	 * @since 9.0.0
 	 */
-	public function getSharesBy(IUser $user, $shareType, $path = null, $reshares = false, $limit = 50, $offset = 0);
+	public function getSharesBy($userId, $shareType, $path = null, $reshares = false, $limit = 50, $offset = 0);
 
 	/**
 	 * Get shares shared with $user.
 	 * Filter by $node if provided
 	 *
-	 * @param IUser $user
+	 * @param string $userId
 	 * @param int $shareType
 	 * @param File|Folder|null $node
 	 * @param int $limit The maximum number of shares returned, -1 for all
@@ -112,7 +112,7 @@ interface IManager {
 	 * @return IShare[]
 	 * @since 9.0.0
 	 */
-	public function getSharedWith(IUser $user, $shareType, $node = null, $limit = 50, $offset = 0);
+	public function getSharedWith($userId, $shareType, $node = null, $limit = 50, $offset = 0);
 
 	/**
 	 * Retrieve a share by the share id.
@@ -223,10 +223,10 @@ interface IManager {
 	/**
 	 * Check if sharing is disabled for the given user
 	 *
-	 * @param IUser $user
+	 * @param string $userId
 	 * @return bool
 	 * @since 9.0.0
 	 */
-	public function sharingDisabledForUser(IUser $user);
+	public function sharingDisabledForUser($userId);
 
 }
diff --git a/lib/public/share/ishare.php b/lib/public/share/ishare.php
index 80e7f7f56ef..5a82436c720 100644
--- a/lib/public/share/ishare.php
+++ b/lib/public/share/ishare.php
@@ -89,7 +89,7 @@ interface IShare {
 	/**
 	 * Set the receiver of this share.
 	 *
-	 * @param IUser|IGroup
+	 * @param string $sharedWith
 	 * @return \OCP\Share\IShare The modified object
 	 * @since 9.0.0
 	 */
@@ -98,7 +98,7 @@ interface IShare {
 	/**
 	 * Get the receiver of this share.
 	 *
-	 * @return IUser|IGroup
+	 * @return string
 	 * @since 9.0.0
 	 */
 	public function getSharedWith();
@@ -142,7 +142,7 @@ interface IShare {
 	/**
 	 * Set the sharer of the path.
 	 *
-	 * @param IUser $sharedBy
+	 * @param string $sharedBy
 	 * @return \OCP\Share\IShare The modified object
 	 * @since 9.0.0
 	 */
@@ -151,7 +151,7 @@ interface IShare {
 	/**
 	 * Get share sharer
 	 *
-	 * @return IUser
+	 * @return string
 	 * @since 9.0.0
 	 */
 	public function getSharedBy();
@@ -159,7 +159,7 @@ interface IShare {
 	/**
 	 * Set the original share owner (who owns the path that is shared)
 	 *
-	 * @param IUser
+	 * @param string $shareOwner
 	 * @return \OCP\Share\IShare The modified object
 	 * @since 9.0.0
 	 */
@@ -168,7 +168,7 @@ interface IShare {
 	/**
 	 * Get the original share owner (who owns the path that is shared)
 	 *
-	 * @return IUser
+	 * @return string
 	 * @since 9.0.0
 	 */
 	public function getShareOwner();
diff --git a/lib/public/share/ishareprovider.php b/lib/public/share/ishareprovider.php
index 42a2881718e..25fa76369ab 100644
--- a/lib/public/share/ishareprovider.php
+++ b/lib/public/share/ishareprovider.php
@@ -74,10 +74,10 @@ interface IShareProvider {
 	 * share from their self then the original group share should still exist.
 	 *
 	 * @param \OCP\Share\IShare $share
-	 * @param IUser $recipient
+	 * @param string $recipient UserId of the recipient
 	 * @since 9.0.0
 	 */
-	public function deleteFromSelf(\OCP\Share\IShare $share, IUser $recipient);
+	public function deleteFromSelf(\OCP\Share\IShare $share, $recipient);
 
 	/**
 	 * Move a share as a recipient.
@@ -86,36 +86,36 @@ interface IShareProvider {
 	 * the target should only be changed for them.
 	 *
 	 * @param \OCP\Share\IShare $share
-	 * @param IUser $recipient
+	 * @param string $recipient userId of recipient
 	 * @return \OCP\Share\IShare
 	 * @since 9.0.0
 	 */
-	public function move(\OCP\Share\IShare $share, IUser $recipient);
+	public function move(\OCP\Share\IShare $share, $recipient);
 
 	/**
 	 * Get all shares by the given user
 	 *
-	 * @param IUser $user
+	 * @param string $userId
 	 * @param int $shareType
 	 * @param \OCP\Files\File|\OCP\Files\Folder $node
 	 * @param bool $reshares Also get the shares where $user is the owner instead of just the shares where $user is the initiator
 	 * @param int $limit The maximum number of shares to be returned, -1 for all shares
 	 * @param int $offset
-	 * @return \OCP\Share\I Share[]
+	 * @return \OCP\Share\IShare Share[]
 	 * @since 9.0.0
 	 */
-	public function getSharesBy(IUser $user, $shareType, $node, $reshares, $limit, $offset);
+	public function getSharesBy($userId, $shareType, $node, $reshares, $limit, $offset);
 
 	/**
 	 * Get share by id
 	 *
 	 * @param int $id
-	 * @param IUser|null $recipient
+	 * @param string|null $recipientId
 	 * @return \OCP\Share\IShare
 	 * @throws ShareNotFound
 	 * @since 9.0.0
 	 */
-	public function getShareById($id, $recipient = null);
+	public function getShareById($id, $recipientId = null);
 
 	/**
 	 * Get shares for a given path
@@ -129,7 +129,7 @@ interface IShareProvider {
 	/**
 	 * Get shared with the given user
 	 *
-	 * @param IUser $user get shares where this user is the recipient
+	 * @param string $userId get shares where this user is the recipient
 	 * @param int $shareType
 	 * @param Node|null $node
 	 * @param int $limit The max number of entries returned, -1 for all
@@ -137,7 +137,7 @@ interface IShareProvider {
 	 * @return \OCP\Share\IShare[]
 	 * @since 9.0.0
 	 */
-	public function getSharedWith(IUser $user, $shareType, $node, $limit, $offset);
+	public function getSharedWith($userId, $shareType, $node, $limit, $offset);
 
 	/**
 	 * Get a share by token
diff --git a/tests/lib/share20/defaultshareprovidertest.php b/tests/lib/share20/defaultshareprovidertest.php
index 32c0b342c41..19f21fba7b1 100644
--- a/tests/lib/share20/defaultshareprovidertest.php
+++ b/tests/lib/share20/defaultshareprovidertest.php
@@ -157,21 +157,13 @@ class DefaultShareProviderTest extends \Test\TestCase {
 				['shareOwner', $shareOwnerFolder],
 			]));
 
-		$this->userManager
-			->method('get')
-			->will($this->returnValueMap([
-				['sharedWith', $sharedWith],
-				['sharedBy', $sharedBy],
-				['shareOwner', $shareOwner],
-			]));
-
 		$share = $this->provider->getShareById($id);
 
 		$this->assertEquals($id, $share->getId());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $share->getShareType());
-		$this->assertEquals($sharedWith, $share->getSharedWith());
-		$this->assertEquals($sharedBy, $share->getSharedBy());
-		$this->assertEquals($shareOwner, $share->getShareOwner());
+		$this->assertEquals('sharedWith', $share->getSharedWith());
+		$this->assertEquals('sharedBy', $share->getSharedBy());
+		$this->assertEquals('shareOwner', $share->getShareOwner());
 		$this->assertEquals($ownerPath, $share->getNode());
 		$this->assertEquals(13, $share->getPermissions());
 		$this->assertEquals(null, $share->getToken());
@@ -221,25 +213,13 @@ class DefaultShareProviderTest extends \Test\TestCase {
 						['shareOwner', $shareOwnerFolder],
 				]));
 
-		$this->userManager
-			->method('get')
-			->will($this->returnValueMap([
-				['sharedBy', $sharedBy],
-				['shareOwner', $shareOwner],
-			]));
-		$this->groupManager
-			->expects($this->once())
-			->method('get')
-			->with('sharedWith')
-			->willReturn($sharedWith);
-
 		$share = $this->provider->getShareById($id);
 
 		$this->assertEquals($id, $share->getId());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_GROUP, $share->getShareType());
-		$this->assertEquals($sharedWith, $share->getSharedWith());
-		$this->assertEquals($sharedBy, $share->getSharedBy());
-		$this->assertEquals($shareOwner, $share->getShareOwner());
+		$this->assertEquals('sharedWith', $share->getSharedWith());
+		$this->assertEquals('sharedBy', $share->getSharedBy());
+		$this->assertEquals('shareOwner', $share->getShareOwner());
 		$this->assertEquals($ownerPath, $share->getNode());
 		$this->assertEquals(13, $share->getPermissions());
 		$this->assertEquals(null, $share->getToken());
@@ -271,13 +251,13 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		]));
 		$this->groupManager->method('get')->with('group0')->willReturn($group0);
 
-		$share = $this->provider->getShareById($id, $user1);
+		$share = $this->provider->getShareById($id, 'user1');
 
 		$this->assertEquals($id, $share->getId());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_GROUP, $share->getShareType());
-		$this->assertSame($group0, $share->getSharedWith());
-		$this->assertSame($user0, $share->getSharedBy());
-		$this->assertSame($user0, $share->getShareOwner());
+		$this->assertSame('group0', $share->getSharedWith());
+		$this->assertSame('user0', $share->getSharedBy());
+		$this->assertSame('user0', $share->getShareOwner());
 		$this->assertSame($node, $share->getNode());
 		$this->assertEquals(0, $share->getPermissions());
 		$this->assertEquals(null, $share->getToken());
@@ -339,8 +319,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->assertEquals($id, $share->getId());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_LINK, $share->getShareType());
 		$this->assertEquals('sharedWith', $share->getPassword());
-		$this->assertEquals($sharedBy, $share->getSharedBy());
-		$this->assertEquals($shareOwner, $share->getShareOwner());
+		$this->assertEquals('sharedBy', $share->getSharedBy());
+		$this->assertEquals('shareOwner', $share->getShareOwner());
 		$this->assertEquals($ownerPath, $share->getNode());
 		$this->assertEquals(13, $share->getPermissions());
 		$this->assertEquals('token', $share->getToken());
@@ -559,9 +539,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		//Child1
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $children[0]->getShareType());
-		$this->assertEquals($user1, $children[0]->getSharedWith());
-		$this->assertEquals($user2, $children[0]->getSharedBy());
-		$this->assertEquals($shareOwner, $children[0]->getShareOwner());
+		$this->assertEquals('user1', $children[0]->getSharedWith());
+		$this->assertEquals('user2', $children[0]->getSharedBy());
+		$this->assertEquals('shareOwner', $children[0]->getShareOwner());
 		$this->assertEquals($ownerPath, $children[0]->getNode());
 		$this->assertEquals(2, $children[0]->getPermissions());
 		$this->assertEquals(null, $children[0]->getToken());
@@ -570,9 +550,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		//Child2
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_GROUP, $children[1]->getShareType());
-		$this->assertEquals($group1, $children[1]->getSharedWith());
-		$this->assertEquals($user3, $children[1]->getSharedBy());
-		$this->assertEquals($shareOwner, $children[1]->getShareOwner());
+		$this->assertEquals('group1', $children[1]->getSharedWith());
+		$this->assertEquals('user3', $children[1]->getSharedBy());
+		$this->assertEquals('shareOwner', $children[1]->getShareOwner());
 		$this->assertEquals($ownerPath, $children[1]->getNode());
 		$this->assertEquals(4, $children[1]->getPermissions());
 		$this->assertEquals(null, $children[1]->getToken());
@@ -583,21 +563,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 	public function testCreateUserShare() {
 		$share = new \OC\Share20\Share();
 
-		$sharedWith = $this->getMock('OCP\IUser');
-		$sharedWith->method('getUID')->willReturn('sharedWith');
-		$sharedBy = $this->getMock('OCP\IUser');
-		$sharedBy->method('getUID')->willReturn('sharedBy');
 		$shareOwner = $this->getMock('OCP\IUser');
 		$shareOwner->method('getUID')->WillReturn('shareOwner');
 
-		$this->userManager
-			->method('get')
-			->will($this->returnValueMap([
-				['sharedWith', $sharedWith],
-				['sharedBy', $sharedBy],
-				['shareOwner', $shareOwner],
-			]));
-
 		$path = $this->getMock('\OCP\Files\File');
 		$path->method('getId')->willReturn(100);
 		$path->method('getOwner')->willReturn($shareOwner);
@@ -619,9 +587,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 			->willReturn([$path]);
 
 		$share->setShareType(\OCP\Share::SHARE_TYPE_USER);
-		$share->setSharedWith($sharedWith);
-		$share->setSharedBy($sharedBy);
-		$share->setShareOwner($shareOwner);
+		$share->setSharedWith('sharedWith');
+		$share->setSharedBy('sharedBy');
+		$share->setShareOwner('shareOwner');
 		$share->setNode($path);
 		$share->setPermissions(1);
 		$share->setTarget('/target');
@@ -631,9 +599,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->assertNotNull($share2->getId());
 		$this->assertSame('ocinternal:'.$share2->getId(), $share2->getFullId());
 		$this->assertSame(\OCP\Share::SHARE_TYPE_USER, $share2->getShareType());
-		$this->assertSame($sharedWith, $share2->getSharedWith());
-		$this->assertSame($sharedBy, $share2->getSharedBy());
-		$this->assertSame($shareOwner, $share2->getShareOwner());
+		$this->assertSame('sharedWith', $share2->getSharedWith());
+		$this->assertSame('sharedBy', $share2->getSharedBy());
+		$this->assertSame('shareOwner', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 		$this->assertSame('/target', $share2->getTarget());
 		$this->assertLessThanOrEqual(new \DateTime(), $share2->getShareTime());
@@ -643,23 +611,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 	public function testCreateGroupShare() {
 		$share = new \OC\Share20\Share();
 
-		$sharedWith = $this->getMock('OCP\IGroup');
-		$sharedWith->method('getGID')->willReturn('sharedWith');
-		$sharedBy = $this->getMock('OCP\IUser');
-		$sharedBy->method('getUID')->willReturn('sharedBy');
-		$shareOwner = $this->getMock('OCP\IUser');
-		$shareOwner->method('getUID')->WillReturn('shareOwner');
-
-		$this->userManager
-			->method('get')
-			->will($this->returnValueMap([
-				['sharedBy', $sharedBy],
-				['shareOwner', $shareOwner],
-			]));
-		$this->groupManager
-			->method('get')
-			->with('sharedWith')
-			->willReturn($sharedWith);
+		$shareOwner = $this->getMock('\OCP\IUser');
+		$shareOwner->method('getUID')->willReturn('shareOwner');
 
 		$path = $this->getMock('\OCP\Files\Folder');
 		$path->method('getId')->willReturn(100);
@@ -682,9 +635,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 			->willReturn([$path]);
 
 		$share->setShareType(\OCP\Share::SHARE_TYPE_GROUP);
-		$share->setSharedWith($sharedWith);
-		$share->setSharedBy($sharedBy);
-		$share->setShareOwner($shareOwner);
+		$share->setSharedWith('sharedWith');
+		$share->setSharedBy('sharedBy');
+		$share->setShareOwner('shareOwner');
 		$share->setNode($path);
 		$share->setPermissions(1);
 		$share->setTarget('/target');
@@ -694,9 +647,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->assertNotNull($share2->getId());
 		$this->assertSame('ocinternal:'.$share2->getId(), $share2->getFullId());
 		$this->assertSame(\OCP\Share::SHARE_TYPE_GROUP, $share2->getShareType());
-		$this->assertSame($sharedWith, $share2->getSharedWith());
-		$this->assertSame($sharedBy, $share2->getSharedBy());
-		$this->assertSame($shareOwner, $share2->getShareOwner());
+		$this->assertSame('sharedWith', $share2->getSharedWith());
+		$this->assertSame('sharedBy', $share2->getSharedBy());
+		$this->assertSame('shareOwner', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 		$this->assertSame('/target', $share2->getTarget());
 		$this->assertLessThanOrEqual(new \DateTime(), $share2->getShareTime());
@@ -706,17 +659,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 	public function testCreateLinkShare() {
 		$share = new \OC\Share20\Share();
 
-		$sharedBy = $this->getMock('OCP\IUser');
-		$sharedBy->method('getUID')->willReturn('sharedBy');
-		$shareOwner = $this->getMock('OCP\IUser');
-		$shareOwner->method('getUID')->WillReturn('shareOwner');
-
-		$this->userManager
-				->method('get')
-				->will($this->returnValueMap([
-						['sharedBy', $sharedBy],
-						['shareOwner', $shareOwner],
-				]));
+		$shareOwner = $this->getMock('\OCP\IUser');
+		$shareOwner->method('getUID')->willReturn('shareOwner');
 
 		$path = $this->getMock('\OCP\Files\Folder');
 		$path->method('getId')->willReturn(100);
@@ -739,8 +683,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 				->willReturn([$path]);
 
 		$share->setShareType(\OCP\Share::SHARE_TYPE_LINK);
-		$share->setSharedBy($sharedBy);
-		$share->setShareOwner($shareOwner);
+		$share->setSharedBy('sharedBy');
+		$share->setShareOwner('shareOwner');
 		$share->setNode($path);
 		$share->setPermissions(1);
 		$share->setPassword('password');
@@ -754,8 +698,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->assertNotNull($share2->getId());
 		$this->assertSame('ocinternal:'.$share2->getId(), $share2->getFullId());
 		$this->assertSame(\OCP\Share::SHARE_TYPE_LINK, $share2->getShareType());
-		$this->assertSame($sharedBy, $share2->getSharedBy());
-		$this->assertSame($shareOwner, $share2->getShareOwner());
+		$this->assertSame('sharedBy', $share2->getSharedBy());
+		$this->assertSame('shareOwner', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 		$this->assertSame('/target', $share2->getTarget());
 		$this->assertLessThanOrEqual(new \DateTime(), $share2->getShareTime());
@@ -783,17 +727,6 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$qb->execute();
 		$id = $qb->getLastInsertId();
 
-		$owner = $this->getMock('\OCP\IUser');
-		$owner->method('getUID')->willReturn('shareOwner');
-		$initiator = $this->getMock('\OCP\IUser');
-		$initiator->method('getUID')->willReturn('sharedBy');
-
-		$this->userManager->method('get')
-			->will($this->returnValueMap([
-				['sharedBy', $initiator],
-				['shareOwner', $owner],
-			]));
-
 		$file = $this->getMock('\OCP\Files\File');
 
 		$this->rootFolder->method('getUserFolder')->with('shareOwner')->will($this->returnSelf());
@@ -801,8 +734,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareByToken('secrettoken');
 		$this->assertEquals($id, $share->getId());
-		$this->assertSame($owner, $share->getShareOwner());
-		$this->assertSame($initiator, $share->getSharedBy());
+		$this->assertSame('shareOwner', $share->getShareOwner());
+		$this->assertSame('sharedBy', $share->getSharedBy());
 		$this->assertSame('secrettoken', $share->getToken());
 		$this->assertSame('password', $share->getPassword());
 		$this->assertSame(null, $share->getSharedWith());
@@ -845,31 +778,18 @@ class DefaultShareProviderTest extends \Test\TestCase {
 			]);
 		$this->assertEquals(1, $qb->execute());
 
-		$user = $this->getMock('\OCP\IUser');
-		$user->method('getUID')->willReturn('sharedWith');
-		$owner = $this->getMock('\OCP\IUser');
-		$owner->method('getUID')->willReturn('shareOwner');
-		$initiator = $this->getMock('\OCP\IUser');
-		$initiator->method('getUID')->willReturn('sharedBy');
-
-		$this->userManager->method('get')->willReturnMap([
-			['sharedWith', $user],
-			['shareOwner', $owner],
-			['sharedBy', $initiator],
-		]);
-
 		$file = $this->getMock('\OCP\Files\File');
 		$this->rootFolder->method('getUserFolder')->with('shareOwner')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(42)->willReturn([$file]);
 
-		$share = $this->provider->getSharedWith($user, \OCP\Share::SHARE_TYPE_USER, null, 1 , 0);
+		$share = $this->provider->getSharedWith('sharedWith', \OCP\Share::SHARE_TYPE_USER, null, 1 , 0);
 		$this->assertCount(1, $share);
 
 		$share = $share[0];
 		$this->assertEquals($id, $share->getId());
-		$this->assertEquals($user, $share->getSharedWith());
-		$this->assertEquals($owner, $share->getShareOwner());
-		$this->assertEquals($initiator, $share->getSharedBy());
+		$this->assertEquals('sharedWith', $share->getSharedWith());
+		$this->assertEquals('shareOwner', $share->getShareOwner());
+		$this->assertEquals('sharedBy', $share->getSharedBy());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $share->getShareType());
 	}
 
@@ -922,6 +842,7 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$initiator->method('getUID')->willReturn('sharedBy');
 
 		$this->userManager->method('get')->willReturnMap([
+			['sharedWith', $user],
 			['shareOwner', $owner],
 			['sharedBy', $initiator],
 		]);
@@ -932,14 +853,14 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->rootFolder->method('getUserFolder')->with('shareOwner')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(42)->willReturn([$file]);
 
-		$share = $this->provider->getSharedWith($user, \OCP\Share::SHARE_TYPE_GROUP, null, 20 , 1);
+		$share = $this->provider->getSharedWith('sharedWith', \OCP\Share::SHARE_TYPE_GROUP, null, 20 , 1);
 		$this->assertCount(1, $share);
 
 		$share = $share[0];
 		$this->assertEquals($id, $share->getId());
-		$this->assertEquals($group, $share->getSharedWith());
-		$this->assertEquals($owner, $share->getShareOwner());
-		$this->assertEquals($initiator, $share->getSharedBy());
+		$this->assertEquals('sharedWith', $share->getSharedWith());
+		$this->assertEquals('shareOwner', $share->getShareOwner());
+		$this->assertEquals('sharedBy', $share->getSharedBy());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_GROUP, $share->getShareType());
 	}
 
@@ -1007,6 +928,7 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$initiator->method('getUID')->willReturn('sharedBy');
 
 		$this->userManager->method('get')->willReturnMap([
+			['user', $user],
 			['shareOwner', $owner],
 			['sharedBy', $initiator],
 		]);
@@ -1017,14 +939,14 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->rootFolder->method('getUserFolder')->with('shareOwner')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(42)->willReturn([$file]);
 
-		$share = $this->provider->getSharedWith($user, \OCP\Share::SHARE_TYPE_GROUP, null, -1, 0);
+		$share = $this->provider->getSharedWith('user', \OCP\Share::SHARE_TYPE_GROUP, null, -1, 0);
 		$this->assertCount(1, $share);
 
 		$share = $share[0];
 		$this->assertSame($id, $share->getId());
-		$this->assertSame($group, $share->getSharedWith());
-		$this->assertSame($owner, $share->getShareOwner());
-		$this->assertSame($initiator, $share->getSharedBy());
+		$this->assertSame('sharedWith', $share->getSharedWith());
+		$this->assertSame('shareOwner', $share->getShareOwner());
+		$this->assertSame('sharedBy', $share->getSharedBy());
 		$this->assertSame(\OCP\Share::SHARE_TYPE_GROUP, $share->getShareType());
 		$this->assertSame(0, $share->getPermissions());
 		$this->assertSame('userTarget', $share->getTarget());
@@ -1051,14 +973,14 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->rootFolder->method('getUserFolder')->with('user1')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(43)->willReturn([$file]);
 
-		$share = $this->provider->getSharedWith($user0, \OCP\Share::SHARE_TYPE_USER, $file, -1, 0);
+		$share = $this->provider->getSharedWith('user0', \OCP\Share::SHARE_TYPE_USER, $file, -1, 0);
 		$this->assertCount(1, $share);
 
 		$share = $share[0];
 		$this->assertEquals($id, $share->getId());
-		$this->assertSame($user0, $share->getSharedWith());
-		$this->assertSame($user1, $share->getShareOwner());
-		$this->assertSame($user1, $share->getSharedBy());
+		$this->assertSame('user0', $share->getSharedWith());
+		$this->assertSame('user1', $share->getShareOwner());
+		$this->assertSame('user1', $share->getSharedBy());
 		$this->assertSame($file, $share->getNode());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $share->getShareType());
 	}
@@ -1090,14 +1012,14 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->rootFolder->method('getUserFolder')->with('user1')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(43)->willReturn([$node]);
 
-		$share = $this->provider->getSharedWith($user0, \OCP\Share::SHARE_TYPE_GROUP, $node, -1, 0);
+		$share = $this->provider->getSharedWith('user0', \OCP\Share::SHARE_TYPE_GROUP, $node, -1, 0);
 		$this->assertCount(1, $share);
 
 		$share = $share[0];
 		$this->assertEquals($id, $share->getId());
-		$this->assertSame($group0, $share->getSharedWith());
-		$this->assertSame($user1, $share->getShareOwner());
-		$this->assertSame($user1, $share->getSharedBy());
+		$this->assertSame('group0', $share->getSharedWith());
+		$this->assertSame('user1', $share->getShareOwner());
+		$this->assertSame('user1', $share->getSharedBy());
 		$this->assertSame($node, $share->getNode());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_GROUP, $share->getShareType());
 	}
@@ -1133,31 +1055,18 @@ class DefaultShareProviderTest extends \Test\TestCase {
 			]);
 		$this->assertEquals(1, $qb->execute());
 
-		$user = $this->getMock('\OCP\IUser');
-		$user->method('getUID')->willReturn('sharedWith');
-		$owner = $this->getMock('\OCP\IUser');
-		$owner->method('getUID')->willReturn('shareOwner');
-		$initiator = $this->getMock('\OCP\IUser');
-		$initiator->method('getUID')->willReturn('sharedBy');
-
-		$this->userManager->method('get')->willReturnMap([
-			['sharedWith', $user],
-			['shareOwner', $owner],
-			['sharedBy', $initiator],
-		]);
-
 		$file = $this->getMock('\OCP\Files\File');
 		$this->rootFolder->method('getUserFolder')->with('shareOwner')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(42)->willReturn([$file]);
 
-		$share = $this->provider->getSharesBy($initiator, \OCP\Share::SHARE_TYPE_USER, null, false, 1, 0);
+		$share = $this->provider->getSharesBy('sharedBy', \OCP\Share::SHARE_TYPE_USER, null, false, 1, 0);
 		$this->assertCount(1, $share);
 
 		$share = $share[0];
 		$this->assertEquals($id, $share->getId());
-		$this->assertEquals($user, $share->getSharedWith());
-		$this->assertEquals($owner, $share->getShareOwner());
-		$this->assertEquals($initiator, $share->getSharedBy());
+		$this->assertEquals('sharedWith', $share->getSharedWith());
+		$this->assertEquals('shareOwner', $share->getShareOwner());
+		$this->assertEquals('sharedBy', $share->getSharedBy());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $share->getShareType());
 		$this->assertEquals(13, $share->getPermissions());
 		$this->assertEquals('myTarget', $share->getTarget());
@@ -1194,32 +1103,19 @@ class DefaultShareProviderTest extends \Test\TestCase {
 			]);
 		$this->assertEquals(1, $qb->execute());
 
-		$user = $this->getMock('\OCP\IUser');
-		$user->method('getUID')->willReturn('sharedWith');
-		$owner = $this->getMock('\OCP\IUser');
-		$owner->method('getUID')->willReturn('shareOwner');
-		$initiator = $this->getMock('\OCP\IUser');
-		$initiator->method('getUID')->willReturn('sharedBy');
-
-		$this->userManager->method('get')->willReturnMap([
-			['sharedWith', $user],
-			['shareOwner', $owner],
-			['sharedBy', $initiator],
-		]);
-
 		$file = $this->getMock('\OCP\Files\File');
 		$file->method('getId')->willReturn(42);
 		$this->rootFolder->method('getUserFolder')->with('shareOwner')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(42)->willReturn([$file]);
 
-		$share = $this->provider->getSharesBy($initiator, \OCP\Share::SHARE_TYPE_USER, $file, false, 1, 0);
+		$share = $this->provider->getSharesBy('sharedBy', \OCP\Share::SHARE_TYPE_USER, $file, false, 1, 0);
 		$this->assertCount(1, $share);
 
 		$share = $share[0];
 		$this->assertEquals($id, $share->getId());
-		$this->assertEquals($user, $share->getSharedWith());
-		$this->assertEquals($owner, $share->getShareOwner());
-		$this->assertEquals($initiator, $share->getSharedBy());
+		$this->assertEquals('sharedWith', $share->getSharedWith());
+		$this->assertEquals('shareOwner', $share->getShareOwner());
+		$this->assertEquals('sharedBy', $share->getSharedBy());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $share->getShareType());
 		$this->assertEquals(13, $share->getPermissions());
 		$this->assertEquals('myTarget', $share->getTarget());
@@ -1256,41 +1152,28 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->assertEquals(1, $qb->execute());
 		$id2 = $qb->getLastInsertId();
 
-		$user = $this->getMock('\OCP\IUser');
-		$user->method('getUID')->willReturn('sharedWith');
-		$owner = $this->getMock('\OCP\IUser');
-		$owner->method('getUID')->willReturn('shareOwner');
-		$initiator = $this->getMock('\OCP\IUser');
-		$initiator->method('getUID')->willReturn('sharedBy');
-
-		$this->userManager->method('get')->willReturnMap([
-			['sharedWith', $user],
-			['shareOwner', $owner],
-			['sharedBy', $initiator],
-		]);
-
 		$file = $this->getMock('\OCP\Files\File');
 		$file->method('getId')->willReturn(42);
 		$this->rootFolder->method('getUserFolder')->with('shareOwner')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->with(42)->willReturn([$file]);
 
-		$shares = $this->provider->getSharesBy($owner, \OCP\Share::SHARE_TYPE_USER, null, true, -1, 0);
+		$shares = $this->provider->getSharesBy('shareOwner', \OCP\Share::SHARE_TYPE_USER, null, true, -1, 0);
 		$this->assertCount(2, $shares);
 
 		$share = $shares[0];
 		$this->assertEquals($id1, $share->getId());
-		$this->assertSame($user, $share->getSharedWith());
-		$this->assertSame($owner, $share->getShareOwner());
-		$this->assertSame($owner, $share->getSharedBy());
+		$this->assertSame('sharedWith', $share->getSharedWith());
+		$this->assertSame('shareOwner', $share->getShareOwner());
+		$this->assertSame('shareOwner', $share->getSharedBy());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $share->getShareType());
 		$this->assertEquals(13, $share->getPermissions());
 		$this->assertEquals('myTarget', $share->getTarget());
 
 		$share = $shares[1];
 		$this->assertEquals($id2, $share->getId());
-		$this->assertSame($user, $share->getSharedWith());
-		$this->assertSame($owner, $share->getShareOwner());
-		$this->assertSame($initiator, $share->getSharedBy());
+		$this->assertSame('sharedWith', $share->getSharedWith());
+		$this->assertSame('shareOwner', $share->getShareOwner());
+		$this->assertSame('sharedBy', $share->getSharedBy());
 		$this->assertEquals(\OCP\Share::SHARE_TYPE_USER, $share->getShareType());
 		$this->assertEquals(0, $share->getPermissions());
 		$this->assertEquals('userTarget', $share->getTarget());
@@ -1334,7 +1217,7 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareById($id);
 
-		$this->provider->deleteFromSelf($share, $user2);
+		$this->provider->deleteFromSelf($share, 'user2');
 
 		$qb = $this->dbConn->getQueryBuilder();
 		$stmt = $qb->select('*')
@@ -1405,7 +1288,7 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareById($id);
 
-		$this->provider->deleteFromSelf($share, $user2);
+		$this->provider->deleteFromSelf($share, 'user2');
 
 		$qb = $this->dbConn->getQueryBuilder();
 		$stmt = $qb->select('*')
@@ -1465,7 +1348,7 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareById($id);
 
-		$this->provider->deleteFromSelf($share, $user2);
+		$this->provider->deleteFromSelf($share, 'user2');
 	}
 
 	public function testDeleteFromSelfUser() {
@@ -1501,7 +1384,7 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareById($id);
 
-		$this->provider->deleteFromSelf($share, $user2);
+		$this->provider->deleteFromSelf($share, 'user2');
 
 		$qb = $this->dbConn->getQueryBuilder();
 		$stmt = $qb->select('*')
@@ -1627,18 +1510,18 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareById($id);
 
-		$share->setSharedWith($users['user3']);
-		$share->setSharedBy($users['user4']);
-		$share->setShareOwner($users['user5']);
+		$share->setSharedWith('user3');
+		$share->setSharedBy('user4');
+		$share->setShareOwner('user5');
 		$share->setNode($file2);
 		$share->setPermissions(1);
 
 		$share2 = $this->provider->update($share);
 
 		$this->assertEquals($id, $share2->getId());
-		$this->assertSame($users['user3'], $share2->getSharedWith());
-		$this->assertSame($users['user4'], $share2->getSharedBy());
-		$this->assertSame($users['user5'], $share2->getShareOwner());
+		$this->assertSame('user3', $share2->getSharedWith());
+		$this->assertSame('user4', $share2->getSharedBy());
+		$this->assertSame('user5', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 	}
 
@@ -1677,8 +1560,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$share = $this->provider->getShareById($id);
 
 		$share->setPassword('password');
-		$share->setSharedBy($users['user4']);
-		$share->setShareOwner($users['user5']);
+		$share->setSharedBy('user4');
+		$share->setShareOwner('user5');
 		$share->setNode($file2);
 		$share->setPermissions(1);
 
@@ -1686,8 +1569,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$this->assertEquals($id, $share2->getId());
 		$this->assertEquals('password', $share->getPassword());
-		$this->assertSame($users['user4'], $share2->getSharedBy());
-		$this->assertSame($users['user5'], $share2->getShareOwner());
+		$this->assertSame('user4', $share2->getSharedBy());
+		$this->assertSame('user5', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 	}
 
@@ -1726,8 +1609,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$share = $this->provider->getShareById($id);
 
 		$share->setPassword(null);
-		$share->setSharedBy($users['user4']);
-		$share->setShareOwner($users['user5']);
+		$share->setSharedBy('user4');
+		$share->setShareOwner('user5');
 		$share->setNode($file2);
 		$share->setPermissions(1);
 
@@ -1735,8 +1618,8 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$this->assertEquals($id, $share2->getId());
 		$this->assertEquals(null, $share->getPassword());
-		$this->assertSame($users['user4'], $share2->getSharedBy());
-		$this->assertSame($users['user5'], $share2->getShareOwner());
+		$this->assertSame('user4', $share2->getSharedBy());
+		$this->assertSame('user5', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 	}
 
@@ -1787,9 +1670,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareById($id);
 
-		$share->setSharedWith($groups['group0']);
-		$share->setSharedBy($users['user4']);
-		$share->setShareOwner($users['user5']);
+		$share->setSharedWith('group0');
+		$share->setSharedBy('user4');
+		$share->setShareOwner('user5');
 		$share->setNode($file2);
 		$share->setPermissions(1);
 
@@ -1797,9 +1680,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$this->assertEquals($id, $share2->getId());
 		// Group shares do not allow updating the recipient
-		$this->assertSame($groups['group0'], $share2->getSharedWith());
-		$this->assertSame($users['user4'], $share2->getSharedBy());
-		$this->assertSame($users['user5'], $share2->getShareOwner());
+		$this->assertSame('group0', $share2->getSharedWith());
+		$this->assertSame('user4', $share2->getSharedBy());
+		$this->assertSame('user5', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 	}
 
@@ -1856,9 +1739,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$share = $this->provider->getShareById($id);
 
-		$share->setSharedWith($groups['group0']);
-		$share->setSharedBy($users['user4']);
-		$share->setShareOwner($users['user5']);
+		$share->setSharedWith('group0');
+		$share->setSharedBy('user4');
+		$share->setShareOwner('user5');
 		$share->setNode($file2);
 		$share->setPermissions(1);
 
@@ -1866,9 +1749,9 @@ class DefaultShareProviderTest extends \Test\TestCase {
 
 		$this->assertEquals($id, $share2->getId());
 		// Group shares do not allow updating the recipient
-		$this->assertSame($groups['group0'], $share2->getSharedWith());
-		$this->assertSame($users['user4'], $share2->getSharedBy());
-		$this->assertSame($users['user5'], $share2->getShareOwner());
+		$this->assertSame('group0', $share2->getSharedWith());
+		$this->assertSame('user4', $share2->getSharedBy());
+		$this->assertSame('user5', $share2->getShareOwner());
 		$this->assertSame(1, $share2->getPermissions());
 
 		$qb = $this->dbConn->getQueryBuilder();
@@ -1949,18 +1832,18 @@ class DefaultShareProviderTest extends \Test\TestCase {
 		$this->rootFolder->method('getUserFolder')->with('user1')->will($this->returnSelf());
 		$this->rootFolder->method('getById')->willReturn([$folder]);
 
-		$share = $this->provider->getShareById($id, $user0);
+		$share = $this->provider->getShareById($id, 'user0');
 
 		$share->setTarget('/newTarget');
-		$this->provider->move($share, $user0);
+		$this->provider->move($share, 'user0');
 
-		$share = $this->provider->getShareById($id, $user0);
+		$share = $this->provider->getShareById($id, 'user0');
 		$this->assertSame('/newTarget', $share->getTarget());
 
 		$share->setTarget('/ultraNewTarget');
-		$this->provider->move($share, $user0);
+		$this->provider->move($share, 'user0');
 
-		$share = $this->provider->getShareById($id, $user0);
+		$share = $this->provider->getShareById($id, 'user0');
 		$this->assertSame('/ultraNewTarget', $share->getTarget());
 	}
 }
diff --git a/tests/lib/share20/managertest.php b/tests/lib/share20/managertest.php
index 34cc39a77df..aa286cc4719 100644
--- a/tests/lib/share20/managertest.php
+++ b/tests/lib/share20/managertest.php
@@ -20,6 +20,7 @@
  */
 namespace Test\Share20;
 
+use OCP\IUserManager;
 use OCP\Share\IProviderFactory;
 use OCP\Share\IShare;
 use OC\Share20\Manager;
@@ -74,6 +75,9 @@ class ManagerTest extends \Test\TestCase {
 	/** @var DummyFactory */
 	protected $factory;
 
+	/** @var IUserManager */
+	protected $userManager;
+
 	public function setUp() {
 		
 		$this->logger = $this->getMock('\OCP\ILogger');
@@ -82,6 +86,7 @@ class ManagerTest extends \Test\TestCase {
 		$this->hasher = $this->getMock('\OCP\Security\IHasher');
 		$this->mountManager = $this->getMock('\OCP\Files\Mount\IMountManager');
 		$this->groupManager = $this->getMock('\OCP\IGroupManager');
+		$this->userManager = $this->getMock('\OCP\IUserManager');
 
 		$this->l = $this->getMock('\OCP\IL10N');
 		$this->l->method('t')
@@ -99,7 +104,8 @@ class ManagerTest extends \Test\TestCase {
 			$this->mountManager,
 			$this->groupManager,
 			$this->l,
-			$this->factory
+			$this->factory,
+			$this->userManager
 		);
 
 		$this->defaultProvider = $this->getMockBuilder('\OC\Share20\DefaultShareProvider')
@@ -124,7 +130,8 @@ class ManagerTest extends \Test\TestCase {
 				$this->mountManager,
 				$this->groupManager,
 				$this->l,
-				$this->factory
+				$this->factory,
+				$this->userManager
 			]);
 	}
 
@@ -151,24 +158,21 @@ class ManagerTest extends \Test\TestCase {
 		$group->method('getGID')->willReturn('sharedWithGroup');
 	
 		return [
-			[\OCP\Share::SHARE_TYPE_USER, $user, 'sharedWithUser'],
-			[\OCP\Share::SHARE_TYPE_GROUP, $group, 'sharedWithGroup'],
-			[\OCP\Share::SHARE_TYPE_LINK, '', ''],
-			[\OCP\Share::SHARE_TYPE_REMOTE, 'foo@bar.com', 'foo@bar.com'],
+			[\OCP\Share::SHARE_TYPE_USER, 'sharedWithUser'],
+			[\OCP\Share::SHARE_TYPE_GROUP, 'sharedWithGroup'],
+			[\OCP\Share::SHARE_TYPE_LINK, ''],
+			[\OCP\Share::SHARE_TYPE_REMOTE, 'foo@bar.com'],
 		];
 	}
 
 	/**
 	 * @dataProvider dataTestDelete
 	 */
-	public function testDelete($shareType, $sharedWith, $sharedWith_string) {
+	public function testDelete($shareType, $sharedWith) {
 		$manager = $this->createManagerMock()
 			->setMethods(['getShareById', 'deleteChildren'])
 			->getMock();
 
-		$sharedBy = $this->getMock('\OCP\IUser');
-		$sharedBy->method('getUID')->willReturn('sharedBy');
-
 		$path = $this->getMock('\OCP\Files\File');
 		$path->method('getId')->willReturn(1);
 
@@ -177,7 +181,7 @@ class ManagerTest extends \Test\TestCase {
 			->setProviderId('prov')
 			->setShareType($shareType)
 			->setSharedWith($sharedWith)
-			->setSharedBy($sharedBy)
+			->setSharedBy('sharedBy')
 			->setNode($path)
 			->setTarget('myTarget');
 
@@ -198,7 +202,7 @@ class ManagerTest extends \Test\TestCase {
 			'itemType' => 'file',
 			'itemSource' => 1,
 			'shareType' => $shareType,
-			'shareWith' => $sharedWith_string,
+			'shareWith' => $sharedWith,
 			'itemparent' => null,
 			'uidOwner' => 'sharedBy',
 			'fileSource' => 1,
@@ -210,7 +214,7 @@ class ManagerTest extends \Test\TestCase {
 			'itemType' => 'file',
 			'itemSource' => 1,
 			'shareType' => $shareType,
-			'shareWith' => $sharedWith_string,
+			'shareWith' => $sharedWith,
 			'itemparent' => null,
 			'uidOwner' => 'sharedBy',
 			'fileSource' => 1,
@@ -221,7 +225,7 @@ class ManagerTest extends \Test\TestCase {
 					'itemType' => 'file',
 					'itemSource' => 1,
 					'shareType' => $shareType,
-					'shareWith' => $sharedWith_string,
+					'shareWith' => $sharedWith,
 					'itemparent' => null,
 					'uidOwner' => 'sharedBy',
 					'fileSource' => 1,
@@ -248,18 +252,6 @@ class ManagerTest extends \Test\TestCase {
 			->setMethods(['getShareById'])
 			->getMock();
 
-		$sharedBy1 = $this->getMock('\OCP\IUser');
-		$sharedBy1->method('getUID')->willReturn('sharedBy1');
-		$sharedBy2 = $this->getMock('\OCP\IUser');
-		$sharedBy2->method('getUID')->willReturn('sharedBy2');
-		$sharedBy3 = $this->getMock('\OCP\IUser');
-		$sharedBy3->method('getUID')->willReturn('sharedBy3');
-
-		$sharedWith1 = $this->getMock('\OCP\IUser');
-		$sharedWith1->method('getUID')->willReturn('sharedWith1');
-		$sharedWith2 = $this->getMock('\OCP\IGroup');
-		$sharedWith2->method('getGID')->willReturn('sharedWith2');
-
 		$path = $this->getMock('\OCP\Files\File');
 		$path->method('getId')->willReturn(1);
 
@@ -267,8 +259,8 @@ class ManagerTest extends \Test\TestCase {
 		$share1->setId(42)
 			->setProviderId('prov')
 			->setShareType(\OCP\Share::SHARE_TYPE_USER)
-			->setSharedWith($sharedWith1)
-			->setSharedBy($sharedBy1)
+			->setSharedWith('sharedWith1')
+			->setSharedBy('sharedBy1')
 			->setNode($path)
 			->setTarget('myTarget1');
 
@@ -276,8 +268,8 @@ class ManagerTest extends \Test\TestCase {
 		$share2->setId(43)
 			->setProviderId('prov')
 			->setShareType(\OCP\Share::SHARE_TYPE_GROUP)
-			->setSharedWith($sharedWith2)
-			->setSharedBy($sharedBy2)
+			->setSharedWith('sharedWith2')
+			->setSharedBy('sharedBy2')
 			->setNode($path)
 			->setTarget('myTarget2')
 			->setParent(42);
@@ -286,7 +278,7 @@ class ManagerTest extends \Test\TestCase {
 		$share3->setId(44)
 			->setProviderId('prov')
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
-			->setSharedBy($sharedBy3)
+			->setSharedBy('sharedBy3')
 			->setNode($path)
 			->setTarget('myTarget3')
 			->setParent(43);
@@ -504,72 +496,72 @@ class ManagerTest extends \Test\TestCase {
 	}
 
 	public function dataGeneralChecks() {
-		$user = $this->getMock('\OCP\IUser');
-		$user2 = $this->getMock('\OCP\IUser');
-		$group = $this->getMock('\OCP\IGroup');
+		$user0 = 'user0';
+		$user2 = 'user1';
+		$group0 = 'group0';
 
 		$file = $this->getMock('\OCP\Files\File');
 		$node = $this->getMock('\OCP\Files\Node');
 
 		$data = [
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, null, $user, $user, 31, null, null), 'SharedWith should be an IUser', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, $group, $user, $user, 31, null, null), 'SharedWith should be an IUser', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, 'foo@bar.com', $user, $user, 31, null, null), 'SharedWith should be an IUser', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, null, $user, $user, 31, null, null), 'SharedWith should be an IGroup', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, $user2, $user, $user, 31, null, null), 'SharedWith should be an IGroup', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, 'foo@bar.com', $user, $user, 31, null, null), 'SharedWith should be an IGroup', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, $user2, $user, $user, 31, null, null), 'SharedWith should be empty', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, $group, $user, $user, 31, null, null), 'SharedWith should be empty', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, 'foo@bar.com', $user, $user, 31, null, null), 'SharedWith should be empty', true],
-			[$this->createShare(null, -1, $file, null, $user, $user, 31, null, null), 'unkown share type', true],
-
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, $user2, null, $user, 31, null, null), 'SharedBy should be set', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, $group, null, $user, 31, null, null), 'SharedBy should be set', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, null, null, $user, 31, null, null), 'SharedBy should be set', true],
-
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, $user, $user, $user, 31, null, null), 'Can\'t share with yourself', true],
-
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  null, $user2, $user, $user, 31, null, null), 'Path should be set', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, null, $group, $user, $user, 31, null, null), 'Path should be set', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  null, null, $user, $user, 31, null, null), 'Path should be set', true],
-
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $node, $user2, $user, $user, 31, null, null), 'Path should be either a file or a folder', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $node, $group, $user, $user, 31, null, null), 'Path should be either a file or a folder', true],
-			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $node, null, $user, $user, 31, null, null), 'Path should be either a file or a folder', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, null, $user0, $user0, 31, null, null), 'SharedWith is not a valid user', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, $group0, $user0, $user0, 31, null, null), 'SharedWith is not a valid user', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, 'foo@bar.com', $user0, $user0, 31, null, null), 'SharedWith is not a valid user', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, null, $user0, $user0, 31, null, null), 'SharedWith is not a valid group', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, $user2, $user0, $user0, 31, null, null), 'SharedWith is not a valid group', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, 'foo@bar.com', $user0, $user0, 31, null, null), 'SharedWith is not a valid group', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, $user2, $user0, $user0, 31, null, null), 'SharedWith should be empty', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, $group0, $user0, $user0, 31, null, null), 'SharedWith should be empty', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, 'foo@bar.com', $user0, $user0, 31, null, null), 'SharedWith should be empty', true],
+			[$this->createShare(null, -1, $file, null, $user0, $user0, 31, null, null), 'unkown share type', true],
+
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, $user2, null, $user0, 31, null, null), 'SharedBy should be set', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $file, $group0, null, $user0, 31, null, null), 'SharedBy should be set', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $file, null, null, $user0, 31, null, null), 'SharedBy should be set', true],
+
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $file, $user0, $user0, $user0, 31, null, null), 'Can\'t share with yourself', true],
+
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  null, $user2, $user0, $user0, 31, null, null), 'Path should be set', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, null, $group0, $user0, $user0, 31, null, null), 'Path should be set', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  null, null, $user0, $user0, 31, null, null), 'Path should be set', true],
+
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $node, $user2, $user0, $user0, 31, null, null), 'Path should be either a file or a folder', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $node, $group0, $user0, $user0, 31, null, null), 'Path should be either a file or a folder', true],
+			[$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $node, null, $user0, $user0, 31, null, null), 'Path should be either a file or a folder', true],
 		];
 
 		$nonShareAble = $this->getMock('\OCP\Files\Folder');
 		$nonShareAble->method('isShareable')->willReturn(false);
 		$nonShareAble->method('getPath')->willReturn('path');
 
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $nonShareAble, $user2, $user, $user, 31, null, null), 'You are not allowed to share path', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $nonShareAble, $group, $user, $user, 31, null, null), 'You are not allowed to share path', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $nonShareAble, null, $user, $user, 31, null, null), 'You are not allowed to share path', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $nonShareAble, $user2, $user0, $user0, 31, null, null), 'You are not allowed to share path', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $nonShareAble, $group0, $user0, $user0, 31, null, null), 'You are not allowed to share path', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $nonShareAble, null, $user0, $user0, 31, null, null), 'You are not allowed to share path', true];
 
 		$limitedPermssions = $this->getMock('\OCP\Files\File');
 		$limitedPermssions->method('isShareable')->willReturn(true);
 		$limitedPermssions->method('getPermissions')->willReturn(\OCP\Constants::PERMISSION_READ);
 		$limitedPermssions->method('getPath')->willReturn('path');
 
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $limitedPermssions, $user2, $user, $user, null, null, null), 'A share requires permissions', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $limitedPermssions, $group, $user, $user, null, null, null), 'A share requires permissions', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $limitedPermssions, null, $user, $user, null, null, null), 'A share requires permissions', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $limitedPermssions, $user2, $user0, $user0, null, null, null), 'A share requires permissions', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $limitedPermssions, $group0, $user0, $user0, null, null, null), 'A share requires permissions', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $limitedPermssions, null, $user0, $user0, null, null, null), 'A share requires permissions', true];
 
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $limitedPermssions, $user2, $user, $user, 31, null, null), 'Cannot increase permissions of path', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $limitedPermssions, $group, $user, $user, 17, null, null), 'Cannot increase permissions of path', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $limitedPermssions, null, $user, $user, 3, null, null), 'Cannot increase permissions of path', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $limitedPermssions, $user2, $user0, $user0, 31, null, null), 'Cannot increase permissions of path', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $limitedPermssions, $group0, $user0, $user0, 17, null, null), 'Cannot increase permissions of path', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $limitedPermssions, null, $user0, $user0, 3, null, null), 'Cannot increase permissions of path', true];
 
 		$allPermssions = $this->getMock('\OCP\Files\Folder');
 		$allPermssions->method('isShareable')->willReturn(true);
 		$allPermssions->method('getPermissions')->willReturn(\OCP\Constants::PERMISSION_ALL);
 
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $allPermssions, $user2, $user, $user, 30, null, null), 'Shares need at least read permissions', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $allPermssions, $group, $user, $user, 2, null, null), 'Shares need at least read permissions', true];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $allPermssions, null, $user, $user, 16, null, null), 'Shares need at least read permissions', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $allPermssions, $user2, $user0, $user0, 30, null, null), 'Shares need at least read permissions', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $allPermssions, $group0, $user0, $user0, 2, null, null), 'Shares need at least read permissions', true];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $allPermssions, null, $user0, $user0, 16, null, null), 'Shares need at least read permissions', true];
 
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $allPermssions, $user2, $user, $user, 31, null, null), null, false];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $allPermssions, $group, $user, $user, 3, null, null), null, false];
-		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $allPermssions, null, $user, $user, 17, null, null), null, false];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $allPermssions, $user2, $user0, $user0, 31, null, null), null, false];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $allPermssions, $group0, $user0, $user0, 3, null, null), null, false];
+		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $allPermssions, null, $user0, $user0, 17, null, null), null, false];
 
 		return $data;
 	}
@@ -583,6 +575,15 @@ class ManagerTest extends \Test\TestCase {
 	public function testGeneralChecks($share, $exceptionMessage, $exception) {
 		$thrown = null;
 
+		$this->userManager->method('userExists')->will($this->returnValueMap([
+			['user0', true],
+			['user1', true],
+		]));
+
+		$this->groupManager->method('groupExists')->will($this->returnValueMap([
+			['group0', true],
+		]));
+
 		try {
 			$this->invokePrivate($this->manager, 'generalCreateChecks', [$share]);
 			$thrown = false;
@@ -795,7 +796,7 @@ class ManagerTest extends \Test\TestCase {
 
 		$sharedBy = $this->getMock('\OCP\IUser');
 		$sharedWith = $this->getMock('\OCP\IUser');
-		$share->setSharedBy($sharedBy)->setSharedWith($sharedWith);
+		$share->setSharedBy('sharedBy')->setSharedWith('sharedWith');
 
 		$this->groupManager
 			->method('getUserGroupIds')
@@ -806,6 +807,11 @@ class ManagerTest extends \Test\TestCase {
 				])
 			);
 
+		$this->userManager->method('get')->will($this->returnValueMap([
+			['sharedBy', $sharedBy],
+			['sharedWith', $sharedWith],
+		]));
+
 		$this->config
 			->method('getAppValue')
 			->will($this->returnValueMap([
@@ -820,7 +826,7 @@ class ManagerTest extends \Test\TestCase {
 
 		$sharedBy = $this->getMock('\OCP\IUser');
 		$sharedWith = $this->getMock('\OCP\IUser');
-		$share->setSharedBy($sharedBy)->setSharedWith($sharedWith);
+		$share->setSharedBy('sharedBy')->setSharedWith('sharedWith');
 
 		$path = $this->getMock('\OCP\Files\Node');
 		$share->setNode($path);
@@ -834,6 +840,11 @@ class ManagerTest extends \Test\TestCase {
 				])
 			);
 
+		$this->userManager->method('get')->will($this->returnValueMap([
+			['sharedBy', $sharedBy],
+			['sharedWith', $sharedWith],
+		]));
+
 		$this->config
 			->method('getAppValue')
 			->will($this->returnValueMap([
@@ -859,10 +870,10 @@ class ManagerTest extends \Test\TestCase {
 		$sharedWith = $this->getMock('\OCP\IUser');
 		$path = $this->getMock('\OCP\Files\Node');
 
-		$share->setSharedWith($sharedWith)->setNode($path)
+		$share->setSharedWith('sharedWith')->setNode($path)
 			->setProviderId('foo')->setId('bar');
 
-		$share2->setSharedWith($sharedWith)->setNode($path)
+		$share2->setSharedWith('sharedWith')->setNode($path)
 			->setProviderId('foo')->setId('baz');
 
 		$this->defaultProvider
@@ -881,28 +892,32 @@ class ManagerTest extends \Test\TestCase {
 		$share  = $this->manager->newShare();
 
 		$sharedWith = $this->getMock('\OCP\IUser');
-		$owner = $this->getMock('\OCP\IUser');
+		$sharedWith->method('getUID')->willReturn('sharedWith');
+
+		$this->userManager->method('get')->with('sharedWith')->willReturn($sharedWith);
+
 		$path = $this->getMock('\OCP\Files\Node');
 
-		$share->setSharedWith($sharedWith)
+		$share->setSharedWith('sharedWith')
 			->setNode($path)
-			->setShareOwner($owner)
+			->setShareOwner('shareOwner')
 			->setProviderId('foo')
 			->setId('bar');
 
 		$share2 = new \OC\Share20\Share();
 		$owner2 = $this->getMock('\OCP\IUser');
 		$share2->setShareType(\OCP\Share::SHARE_TYPE_GROUP)
-			->setShareOwner($owner2)
+			->setShareOwner('shareOwner2')
 			->setProviderId('foo')
-			->setId('baz');
+			->setId('baz')
+			->setSharedWith('group');
 
 		$group = $this->getMock('\OCP\IGroup');
 		$group->method('inGroup')
 			->with($sharedWith)
 			->willReturn(true);
 
-		$share2->setSharedWith($group);
+		$this->groupManager->method('get')->with('group')->willReturn($group);
 
 		$this->defaultProvider
 			->method('getSharesByPath')
@@ -915,18 +930,18 @@ class ManagerTest extends \Test\TestCase {
 	public function testUserCreateChecksIdenticalPathNotSharedWithUser() {
 		$share = new \OC\Share20\Share();
 		$sharedWith = $this->getMock('\OCP\IUser');
-		$owner = $this->getMock('\OCP\IUser');
 		$path = $this->getMock('\OCP\Files\Node');
-		$share->setSharedWith($sharedWith)
+		$share->setSharedWith('sharedWith')
 			->setNode($path)
-			->setShareOwner($owner)
+			->setShareOwner('shareOwner')
 			->setProviderId('foo')
 			->setId('bar');
 
+		$this->userManager->method('get')->with('sharedWith')->willReturn($sharedWith);
+
 		$share2 = new \OC\Share20\Share();
-		$owner2 = $this->getMock('\OCP\IUser');
 		$share2->setShareType(\OCP\Share::SHARE_TYPE_GROUP)
-			->setShareOwner($owner2)
+			->setShareOwner('shareOwner2')
 			->setProviderId('foo')
 			->setId('baz');
 
@@ -935,7 +950,9 @@ class ManagerTest extends \Test\TestCase {
 			->with($sharedWith)
 			->willReturn(false);
 
-		$share2->setSharedWith($group);
+		$this->groupManager->method('get')->with('group')->willReturn($group);
+
+		$share2->setSharedWith('group');
 
 		$this->defaultProvider
 			->method('getSharesByPath')
@@ -952,11 +969,14 @@ class ManagerTest extends \Test\TestCase {
 	public function testGroupCreateChecksShareWithGroupMembersOnlyNotInGroup() {
 		$share = new \OC\Share20\Share();
 
-		$sharedBy = $this->getMock('\OCP\IUser');
-		$sharedWith = $this->getMock('\OCP\IGroup');
-		$share->setSharedBy($sharedBy)->setSharedWith($sharedWith);
+		$user = $this->getMock('\OCP\IUser');
+		$group = $this->getMock('\OCP\IGroup');
+		$share->setSharedBy('user')->setSharedWith('group');
 
-		$sharedWith->method('inGroup')->with($sharedBy)->willReturn(false);
+		$group->method('inGroup')->with($user)->willReturn(false);
+
+		$this->groupManager->method('get')->with('group')->willReturn($group);
+		$this->userManager->method('get')->with('user')->willReturn($user);
 
 		$this->config
 			->method('getAppValue')
@@ -970,11 +990,14 @@ class ManagerTest extends \Test\TestCase {
 	public function testGroupCreateChecksShareWithGroupMembersOnlyInGroup() {
 		$share = new \OC\Share20\Share();
 
-		$sharedBy = $this->getMock('\OCP\IUser');
-		$sharedWith = $this->getMock('\OCP\IGroup');
-		$share->setSharedBy($sharedBy)->setSharedWith($sharedWith);
+		$user = $this->getMock('\OCP\IUser');
+		$group = $this->getMock('\OCP\IGroup');
+		$share->setSharedBy('user')->setSharedWith('group');
 
-		$sharedWith->method('inGroup')->with($sharedBy)->willReturn(true);
+		$this->userManager->method('get')->with('user')->willReturn($user);
+		$this->groupManager->method('get')->with('group')->willReturn($group);
+
+		$group->method('inGroup')->with($user)->willReturn(true);
 
 		$path = $this->getMock('\OCP\Files\Node');
 		$share->setNode($path);
@@ -999,15 +1022,14 @@ class ManagerTest extends \Test\TestCase {
 	public function testGroupCreateChecksPathAlreadySharedWithSameGroup() {
 		$share = $this->manager->newShare();
 
-		$sharedWith = $this->getMock('\OCP\IGroup');
 		$path = $this->getMock('\OCP\Files\Node');
-		$share->setSharedWith($sharedWith)
+		$share->setSharedWith('sharedWith')
 			->setNode($path)
 			->setProviderId('foo')
 			->setId('bar');
 
 		$share2 = new \OC\Share20\Share();
-		$share2->setSharedWith($sharedWith)
+		$share2->setSharedWith('sharedWith')
 			->setProviderId('foo')
 			->setId('baz');
 
@@ -1021,15 +1043,13 @@ class ManagerTest extends \Test\TestCase {
 	public function testGroupCreateChecksPathAlreadySharedWithDifferentGroup() {
 		$share = new \OC\Share20\Share();
 
-		$sharedWith = $this->getMock('\OCP\IGroup');
-		$share->setSharedWith($sharedWith);
+		$share->setSharedWith('sharedWith');
 
 		$path = $this->getMock('\OCP\Files\Node');
 		$share->setNode($path);
 
 		$share2 = new \OC\Share20\Share();
-		$sharedWith2 = $this->getMock('\OCP\IGroup');
-		$share2->setSharedWith($sharedWith2);
+		$share2->setSharedWith('sharedWith2');
 
 		$this->defaultProvider->method('getSharesByPath')
 			->with($path)
@@ -1238,7 +1258,9 @@ class ManagerTest extends \Test\TestCase {
 			->with($user)
 			->willReturn($groupIds);
 
-		$res = $this->manager->sharingDisabledForUser($user);
+		$this->userManager->method('get')->with('user')->willReturn($user);
+
+		$res = $this->manager->sharingDisabledForUser('user');
 		$this->assertEquals($expected, $res);
 	}
 
@@ -1278,7 +1300,7 @@ class ManagerTest extends \Test\TestCase {
 
 		$user = $this->getMock('\OCP\IUser');
 		$share = $this->manager->newShare();
-		$share->setSharedBy($user);
+		$share->setSharedBy('user');
 
 		$res = $this->invokePrivate($manager, 'canShare', [$share]);
 		$this->assertEquals($expected, $res);
@@ -1303,9 +1325,8 @@ class ManagerTest extends \Test\TestCase {
 			->setMethods(['canShare', 'generalCreateChecks', 'userCreateChecks', 'pathCreateChecks'])
 			->getMock();
 
-		$sharedWith = $this->getMock('\OCP\IUser');
-		$sharedBy = $this->getMock('\OCP\IUser');
 		$shareOwner = $this->getMock('\OCP\IUser');
+		$shareOwner->method('getUID')->willReturn('shareOwner');
 
 		$path = $this->getMock('\OCP\Files\File');
 		$path->method('getOwner')->willReturn($shareOwner);
@@ -1315,8 +1336,8 @@ class ManagerTest extends \Test\TestCase {
 			null,
 			\OCP\Share::SHARE_TYPE_USER,
 			$path,
-			$sharedWith,
-			$sharedBy,
+			'sharedWith',
+			'sharedBy',
 			null,
 			\OCP\Constants::PERMISSION_ALL);
 
@@ -1342,7 +1363,7 @@ class ManagerTest extends \Test\TestCase {
 
 		$share->expects($this->once())
 			->method('setShareOwner')
-			->with($shareOwner);
+			->with('shareOwner');
 		$share->expects($this->once())
 			->method('setTarget')
 			->with('/target');
@@ -1355,9 +1376,8 @@ class ManagerTest extends \Test\TestCase {
 			->setMethods(['canShare', 'generalCreateChecks', 'groupCreateChecks', 'pathCreateChecks'])
 			->getMock();
 
-		$sharedWith = $this->getMock('\OCP\IGroup');
-		$sharedBy = $this->getMock('\OCP\IUser');
 		$shareOwner = $this->getMock('\OCP\IUser');
+		$shareOwner->method('getUID')->willReturn('shareOwner');
 
 		$path = $this->getMock('\OCP\Files\File');
 		$path->method('getOwner')->willReturn($shareOwner);
@@ -1367,8 +1387,8 @@ class ManagerTest extends \Test\TestCase {
 			null,
 			\OCP\Share::SHARE_TYPE_GROUP,
 			$path,
-			$sharedWith,
-			$sharedBy,
+			'sharedWith',
+			'sharedBy',
 			null,
 			\OCP\Constants::PERMISSION_ALL);
 
@@ -1394,7 +1414,7 @@ class ManagerTest extends \Test\TestCase {
 
 		$share->expects($this->once())
 			->method('setShareOwner')
-			->with($shareOwner);
+			->with('shareOwner');
 		$share->expects($this->once())
 			->method('setTarget')
 			->with('/target');
@@ -1414,9 +1434,8 @@ class ManagerTest extends \Test\TestCase {
 			])
 			->getMock();
 
-		$sharedBy = $this->getMock('\OCP\IUser');
-		$sharedBy->method('getUID')->willReturn('sharedBy');
 		$shareOwner = $this->getMock('\OCP\IUser');
+		$shareOwner->method('getUID')->willReturn('shareOwner');
 
 		$path = $this->getMock('\OCP\Files\File');
 		$path->method('getOwner')->willReturn($shareOwner);
@@ -1428,7 +1447,7 @@ class ManagerTest extends \Test\TestCase {
 		$share = $this->manager->newShare();
 		$share->setShareType(\OCP\Share::SHARE_TYPE_LINK)
 			->setNode($path)
-			->setSharedBy($sharedBy)
+			->setSharedBy('sharedBy')
 			->setPermissions(\OCP\Constants::PERMISSION_ALL)
 			->setExpirationDate($date)
 			->setPassword('password');
@@ -1515,7 +1534,7 @@ class ManagerTest extends \Test\TestCase {
 		/** @var IShare $share */
 		$share = $manager->createShare($share);
 
-		$this->assertSame($shareOwner, $share->getShareOwner());
+		$this->assertSame('shareOwner', $share->getShareOwner());
 		$this->assertEquals('/target', $share->getTarget());
 		$this->assertSame($date, $share->getExpirationDate());
 		$this->assertEquals('token', $share->getToken());
@@ -1536,9 +1555,8 @@ class ManagerTest extends \Test\TestCase {
 			])
 			->getMock();
 
-		$sharedWith = $this->getMock('\OCP\IUser');
-		$sharedBy = $this->getMock('\OCP\IUser');
 		$shareOwner = $this->getMock('\OCP\IUser');
+		$shareOwner->method('getUID')->willReturn('shareOwner');
 
 		$path = $this->getMock('\OCP\Files\File');
 		$path->method('getOwner')->willReturn($shareOwner);
@@ -1548,8 +1566,8 @@ class ManagerTest extends \Test\TestCase {
 			null,
 			\OCP\Share::SHARE_TYPE_USER,
 			$path,
-			$sharedWith,
-			$sharedBy,
+			'sharedWith',
+			'sharedBy',
 			null,
 			\OCP\Constants::PERMISSION_ALL);
 
@@ -1569,7 +1587,7 @@ class ManagerTest extends \Test\TestCase {
 
 		$share->expects($this->once())
 			->method('setShareOwner')
-			->with($shareOwner);
+			->with('shareOwner');
 		$share->expects($this->once())
 			->method('setTarget')
 			->with('/target');
@@ -1591,7 +1609,8 @@ class ManagerTest extends \Test\TestCase {
 			$this->mountManager,
 			$this->groupManager,
 			$this->l,
-			$factory
+			$factory,
+			$this->userManager
 		);
 
 		$share = $this->getMock('\OCP\Share\IShare');
@@ -1718,12 +1737,9 @@ class ManagerTest extends \Test\TestCase {
 			])
 			->getMock();
 
-		$origGroup = $this->getMock('\OCP\IGroup');
-		$newGroup = $this->getMock('\OCP\IGroup');
-
 		$originalShare = new \OC\Share20\Share();
 		$originalShare->setShareType(\OCP\Share::SHARE_TYPE_GROUP)
-			->setSharedWith($origGroup);
+			->setSharedWith('origGroup');
 
 		$manager->expects($this->once())->method('canShare')->willReturn(true);
 		$manager->expects($this->once())->method('getShareById')->with('foo:42')->willReturn($originalShare);
@@ -1732,7 +1748,7 @@ class ManagerTest extends \Test\TestCase {
 		$share->setProviderId('foo')
 			->setId('42')
 			->setShareType(\OCP\Share::SHARE_TYPE_GROUP)
-			->setSharedWith($newGroup);
+			->setSharedWith('newGroup');
 
 		$manager->updateShare($share);
 	}
@@ -1749,12 +1765,9 @@ class ManagerTest extends \Test\TestCase {
 			])
 			->getMock();
 
-		$origUser = $this->getMock('\OCP\IUser');
-		$newUser = $this->getMock('\OCP\IUser');
-
 		$originalShare = new \OC\Share20\Share();
 		$originalShare->setShareType(\OCP\Share::SHARE_TYPE_USER)
-			->setSharedWith($origUser);
+			->setSharedWith('sharedWith');
 
 		$manager->expects($this->once())->method('canShare')->willReturn(true);
 		$manager->expects($this->once())->method('getShareById')->with('foo:42')->willReturn($originalShare);
@@ -1763,8 +1776,8 @@ class ManagerTest extends \Test\TestCase {
 		$share->setProviderId('foo')
 			->setId('42')
 			->setShareType(\OCP\Share::SHARE_TYPE_USER)
-			->setSharedWith($newUser)
-			->setShareOwner($newUser);
+			->setSharedWith('newUser')
+			->setShareOwner('newUser');
 
 		$manager->updateShare($share);
 	}
@@ -1780,12 +1793,9 @@ class ManagerTest extends \Test\TestCase {
 			])
 			->getMock();
 
-		$origUser = $this->getMock('\OCP\IUser');
-		$newUser = $this->getMock('\OCP\IUser');
-
 		$originalShare = new \OC\Share20\Share();
 		$originalShare->setShareType(\OCP\Share::SHARE_TYPE_USER)
-			->setSharedWith($origUser);
+			->setSharedWith('origUser');
 
 		$manager->expects($this->once())->method('canShare')->willReturn(true);
 		$manager->expects($this->once())->method('getShareById')->with('foo:42')->willReturn($originalShare);
@@ -1794,8 +1804,8 @@ class ManagerTest extends \Test\TestCase {
 		$share->setProviderId('foo')
 			->setId('42')
 			->setShareType(\OCP\Share::SHARE_TYPE_USER)
-			->setSharedWith($origUser)
-			->setShareOwner($newUser);
+			->setSharedWith('origUser')
+			->setShareOwner('newUser');
 
 		$this->defaultProvider->expects($this->once())
 			->method('update')
@@ -1821,12 +1831,9 @@ class ManagerTest extends \Test\TestCase {
 			])
 			->getMock();
 
-		$origGroup = $this->getMock('\OCP\IGroup');
-		$user = $this->getMock('\OCP\IUser');
-
 		$originalShare = new \OC\Share20\Share();
 		$originalShare->setShareType(\OCP\Share::SHARE_TYPE_GROUP)
-			->setSharedWith($origGroup);
+			->setSharedWith('origUser');
 
 		$manager->expects($this->once())->method('canShare')->willReturn(true);
 		$manager->expects($this->once())->method('getShareById')->with('foo:42')->willReturn($originalShare);
@@ -1835,8 +1842,8 @@ class ManagerTest extends \Test\TestCase {
 		$share->setProviderId('foo')
 			->setId('42')
 			->setShareType(\OCP\Share::SHARE_TYPE_GROUP)
-			->setSharedWith($origGroup)
-			->setShareOwner($user);
+			->setSharedWith('origUser')
+			->setShareOwner('owner');
 
 		$this->defaultProvider->expects($this->once())
 			->method('update')
@@ -1864,9 +1871,6 @@ class ManagerTest extends \Test\TestCase {
 			])
 			->getMock();
 
-		$user = $this->getMock('\OCP\IUser');
-		$user->method('getUID')->willReturn('owner');
-
 		$originalShare = new \OC\Share20\Share();
 		$originalShare->setShareType(\OCP\Share::SHARE_TYPE_LINK);
 
@@ -1881,8 +1885,8 @@ class ManagerTest extends \Test\TestCase {
 		$share->setProviderId('foo')
 			->setId('42')
 			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
-			->setSharedBy($user)
-			->setShareOwner($user)
+			->setSharedBy('owner')
+			->setShareOwner('owner')
 			->setPassword('password')
 			->setExpirationDate($tomorrow)
 			->setNode($file);
@@ -1930,24 +1934,20 @@ class ManagerTest extends \Test\TestCase {
 		$share = $this->manager->newShare();
 		$share->setShareType(\OCP\Share::SHARE_TYPE_USER);
 
-		$sharedWith = $this->getMock('\OCP\IUser');
-		$share->setSharedWith($sharedWith);
-
-		$recipient = $this->getMock('\OCP\IUser');
+		$share->setSharedWith('sharedWith');
 
-		$this->manager->moveShare($share, $recipient);
+		$this->manager->moveShare($share, 'recipient');
 	}
 
 	public function testMoveShareUser() {
 		$share = $this->manager->newShare();
 		$share->setShareType(\OCP\Share::SHARE_TYPE_USER);
 
-		$recipient = $this->getMock('\OCP\IUser');
-		$share->setSharedWith($recipient);
+		$share->setSharedWith('recipient');
 
-		$this->defaultProvider->method('move')->with($share, $recipient)->will($this->returnArgument(0));
+		$this->defaultProvider->method('move')->with($share, 'recipient')->will($this->returnArgument(0));
 
-		$this->manager->moveShare($share, $recipient);
+		$this->manager->moveShare($share, 'recipient');
 	}
 
 	/**
@@ -1959,27 +1959,33 @@ class ManagerTest extends \Test\TestCase {
 		$share->setShareType(\OCP\Share::SHARE_TYPE_GROUP);
 
 		$sharedWith = $this->getMock('\OCP\IGroup');
-		$share->setSharedWith($sharedWith);
+		$share->setSharedWith('shareWith');
 
 		$recipient = $this->getMock('\OCP\IUser');
 		$sharedWith->method('inGroup')->with($recipient)->willReturn(false);
 
-		$this->manager->moveShare($share, $recipient);
+		$this->groupManager->method('get')->with('shareWith')->willReturn($sharedWith);
+		$this->userManager->method('get')->with('recipient')->willReturn($recipient);
+
+		$this->manager->moveShare($share, 'recipient');
 	}
 
 	public function testMoveShareGroup() {
 		$share = $this->manager->newShare();
 		$share->setShareType(\OCP\Share::SHARE_TYPE_GROUP);
 
-		$sharedWith = $this->getMock('\OCP\IGroup');
-		$share->setSharedWith($sharedWith);
+		$group = $this->getMock('\OCP\IGroup');
+		$share->setSharedWith('group');
 
 		$recipient = $this->getMock('\OCP\IUser');
-		$sharedWith->method('inGroup')->with($recipient)->willReturn(true);
+		$group->method('inGroup')->with($recipient)->willReturn(true);
 
-		$this->defaultProvider->method('move')->with($share, $recipient)->will($this->returnArgument(0));
+		$this->groupManager->method('get')->with('group')->willReturn($group);
+		$this->userManager->method('get')->with('recipient')->willReturn($recipient);
 
-		$this->manager->moveShare($share, $recipient);
+		$this->defaultProvider->method('move')->with($share, 'recipient')->will($this->returnArgument(0));
+
+		$this->manager->moveShare($share, 'recipient');
 	}
 }