add icommentsmanger and icomment implementation

register CommentsManager service, allow override, document in config.sample.php

don't insert autoincrement ids in tests, because of dislikes from oracle and pgsql

specify timezone in null date

only accepts strings for ID parameter that can be converted to int

replace forgotten hardcoded IDs in tests

react on deleted users

react on file deletion

Postgresql compatibility

lastInsertId needs *PREFIX* with the table name

do not listen for file deletion, because it is not reliable (trashbin, external storages)

add runtime cache for comments

4 files changed, 685 insertions, 0 deletions

diff --git a/tests/lib/comments/comment.php b/tests/lib/comments/comment.php
new file mode 100644
index 00000000000..790aca42967
--- /dev/null
+++ b/tests/lib/comments/comment.php
@@ -0,0 +1,102 @@
+<?php
+
+class Test_Comments_Comment extends Test\TestCase
+{
+
+	public function testSettersValidInput() {
+		$comment = new \OC\Comments\Comment();
+
+		$id = 'comment23';
+		$parentId = 'comment11.5';
+		$childrenCount = 6;
+		$message = 'I like to comment comment';
+		$verb = 'comment';
+		$actor = ['type' => 'user', 'id' => 'alice'];
+		$creationDT = new \DateTime();
+		$latestChildDT = new \DateTime('yesterday');
+		$object = ['type' => 'file', 'id' => 'file64'];
+
+		$comment
+			->setId($id)
+			->setParentId($parentId)
+			->setChildrenCount($childrenCount)
+			->setMessage($message)
+			->setVerb($verb)
+			->setActor($actor['type'], $actor['id'])
+			->setCreationDateTime($creationDT)
+			->setLatestChildDateTime($latestChildDT)
+			->setObject($object['type'], $object['id']);
+
+		$this->assertSame($id, $comment->getId());
+		$this->assertSame($parentId, $comment->getParentId());
+		$this->assertSame($childrenCount, $comment->getChildrenCount());
+		$this->assertSame($message, $comment->getMessage());
+		$this->assertSame($verb, $comment->getVerb());
+		$this->assertSame($actor['type'], $comment->getActorType());
+		$this->assertSame($actor['id'], $comment->getActorId());
+		$this->assertSame($creationDT, $comment->getCreationDateTime());
+		$this->assertSame($latestChildDT, $comment->getLatestChildDateTime());
+		$this->assertSame($object['type'], $comment->getObjectType());
+		$this->assertSame($object['id'], $comment->getObjectId());
+	}
+
+	public function testSetIdIllegalInput() {
+		$comment = new \OC\Comments\Comment();
+
+		$this->setExpectedException('\OCP\Comments\IllegalIDChangeException');
+		$comment->setId('c23');
+		$comment->setId('c17');
+	}
+
+	public function testResetId() {
+		$comment = new \OC\Comments\Comment();
+		$comment->setId('c23');
+		$comment->setId('');
+	}
+
+	public function simpleSetterProvider() {
+		return [
+			['Id'],
+			['ParentId'],
+			['Message'],
+			['Verb'],
+			['ChildrenCount'],
+		];
+	}
+
+	/**
+	 * @dataProvider simpleSetterProvider
+	 */
+	public function testSimpleSetterInvalidInput($field) {
+		$comment = new \OC\Comments\Comment();
+		$setter = 'set' . $field;
+
+		$this->setExpectedException('InvalidArgumentException');
+		// we have no field that is supposed to accept a Bool
+		$comment->$setter(true);
+	}
+
+	public function roleSetterProvider() {
+		return [
+			['Actor', true, true],
+			['Actor', 'user', true],
+			['Actor', true, 'alice'],
+			['Object', true, true],
+			['Object', 'file', true],
+			['Object', true, 'file64'],
+		];
+	}
+
+	/**
+	 * @dataProvider roleSetterProvider
+	 */
+	public function testSetRoleInvalidInput($role, $type, $id){
+		$comment = new \OC\Comments\Comment();
+		$setter = 'set' . $role;
+		$this->setExpectedException('InvalidArgumentException');
+		$comment->$setter($type, $id);
+	}
+
+
+
+}
diff --git a/tests/lib/comments/fakefactory.php b/tests/lib/comments/fakefactory.php
new file mode 100644
index 00000000000..202b02f6411
--- /dev/null
+++ b/tests/lib/comments/fakefactory.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Class Test_Comments_FakeFactory
+ *
+ * this class does not contain any tests. It's sole purpose is to return
+ * a mock of \OCP\Comments\ICommentsManager when getManager() is called.
+ * For mock creation and auto-loading it extends Test\TestCase. I am, uh, really
+ * sorry for this hack.
+ */
+class Test_Comments_FakeFactory extends Test\TestCase implements \OCP\Comments\ICommentsManagerFactory {
+
+	public function testNothing() {
+		// If there would not be at least one test, phpunit would scream failure
+		// So we have one and skip it.
+		$this->markTestSkipped();
+	}
+
+	public function getManager() {
+		return $this->getMock('\OCP\Comments\ICommentsManager');
+	}
+}
diff --git a/tests/lib/comments/manager.php b/tests/lib/comments/manager.php
new file mode 100644
index 00000000000..610dfe51a47
--- /dev/null
+++ b/tests/lib/comments/manager.php
@@ -0,0 +1,560 @@
+<?php
+
+use OCP\Comments\ICommentsManager;
+
+/**
+ * Class Test_Comments_Manager
+ *
+ * @group DB
+ */
+class Test_Comments_Manager extends Test\TestCase
+{
+
+	public function setUp() {
+		parent::setUp();
+
+		$sql = \oc::$server->getDatabaseConnection()->getDatabasePlatform()->getTruncateTableSQL('`*PREFIX*comments`');
+		\oc::$server->getDatabaseConnection()->prepare($sql)->execute();
+	}
+
+	protected function addDatabaseEntry($parentId, $topmostParentId, $creationDT = null, $latestChildDT = null) {
+		if(is_null($creationDT)) {
+			$creationDT = new \DateTime();
+		}
+		if(is_null($latestChildDT)) {
+			$latestChildDT = new \DateTime('yesterday');
+		}
+
+		$qb = \oc::$server->getDatabaseConnection()->getQueryBuilder();
+		$qb
+			->insert('comments')
+			->values([
+					'parent_id'					=> $qb->createNamedParameter($parentId),
+					'topmost_parent_id' 		=> $qb->createNamedParameter($topmostParentId),
+					'children_count' 			=> $qb->createNamedParameter(2),
+					'actor_type' 				=> $qb->createNamedParameter('user'),
+					'actor_id' 					=> $qb->createNamedParameter('alice'),
+					'message' 					=> $qb->createNamedParameter('nice one'),
+					'verb' 						=> $qb->createNamedParameter('comment'),
+					'creation_timestamp' 		=> $qb->createNamedParameter($creationDT, 'datetime'),
+					'latest_child_timestamp'	=> $qb->createNamedParameter($latestChildDT, 'datetime'),
+					'object_type' 				=> $qb->createNamedParameter('file'),
+					'object_id' 				=> $qb->createNamedParameter('file64'),
+			])
+			->execute();
+
+		return \oc::$server->getDatabaseConnection()->lastInsertId('*PREFIX*comments');
+	}
+
+	protected function getManager() {
+		$factory = new \OC\Comments\ManagerFactory();
+		return $factory->getManager();
+	}
+
+	public function testGetCommentNotFound() {
+		$manager = $this->getManager();
+		$this->setExpectedException('\OCP\Comments\NotFoundException');
+		$manager->get('22');
+	}
+
+	public function testGetCommentNotFoundInvalidInput() {
+		$manager = $this->getManager();
+		$this->setExpectedException('\InvalidArgumentException');
+		$manager->get('unexisting22');
+	}
+
+	public function testGetComment() {
+		$manager = $this->getManager();
+
+		$creationDT = new \DateTime();
+		$latestChildDT = new \DateTime('yesterday');
+
+		$qb = \oc::$server->getDatabaseConnection()->getQueryBuilder();
+		$qb
+			->insert('comments')
+			->values([
+					'parent_id'					=> $qb->createNamedParameter('2'),
+					'topmost_parent_id' 		=> $qb->createNamedParameter('1'),
+					'children_count' 			=> $qb->createNamedParameter(2),
+					'actor_type' 				=> $qb->createNamedParameter('user'),
+					'actor_id' 					=> $qb->createNamedParameter('alice'),
+					'message' 					=> $qb->createNamedParameter('nice one'),
+					'verb' 						=> $qb->createNamedParameter('comment'),
+					'creation_timestamp' 		=> $qb->createNamedParameter($creationDT, 'datetime'),
+					'latest_child_timestamp'	=> $qb->createNamedParameter($latestChildDT, 'datetime'),
+					'object_type' 				=> $qb->createNamedParameter('file'),
+					'object_id' 				=> $qb->createNamedParameter('file64'),
+			])
+			->execute();
+
+		$id = strval(\oc::$server->getDatabaseConnection()->lastInsertId('*PREFIX*comments'));
+
+		$comment = $manager->get($id);
+		$this->assertTrue($comment instanceof \OCP\Comments\IComment);
+		$this->assertSame($comment->getId(), $id);
+		$this->assertSame($comment->getParentId(), '2');
+		$this->assertSame($comment->getTopmostParentId(), '1');
+		$this->assertSame($comment->getChildrenCount(), 2);
+		$this->assertSame($comment->getActorType(), 'user');
+		$this->assertSame($comment->getActorId(), 'alice');
+		$this->assertSame($comment->getMessage(), 'nice one');
+		$this->assertSame($comment->getVerb(), 'comment');
+		$this->assertSame($comment->getObjectType(), 'file');
+		$this->assertSame($comment->getObjectId(), 'file64');
+		$this->assertEquals($comment->getCreationDateTime(), $creationDT);
+		$this->assertEquals($comment->getLatestChildDateTime(), $latestChildDT);
+	}
+
+	public function testGetTreeNotFound() {
+		$manager = $this->getManager();
+		$this->setExpectedException('\OCP\Comments\NotFoundException');
+		$manager->getTree('22');
+	}
+
+	public function testGetTreeNotFoundInvalidIpnut() {
+		$manager = $this->getManager();
+		$this->setExpectedException('\InvalidArgumentException');
+		$manager->getTree('unexisting22');
+	}
+
+	public function testGetTree() {
+		$headId = $this->addDatabaseEntry(0, 0);
+
+		$this->addDatabaseEntry($headId, $headId, new \DateTime('-3 hours'));
+		$this->addDatabaseEntry($headId, $headId, new \DateTime('-2 hours'));
+		$id = $this->addDatabaseEntry($headId, $headId, new \DateTime('-1 hour'));
+
+		$manager = $this->getManager();
+		$tree = $manager->getTree($headId);
+
+		// Verifying the root comment
+		$this->assertTrue(isset($tree['comment']));
+		$this->assertTrue($tree['comment'] instanceof \OCP\Comments\IComment);
+		$this->assertSame($tree['comment']->getId(), strval($headId));
+		$this->assertTrue(isset($tree['replies']));
+		$this->assertSame(count($tree['replies']), 3);
+
+		// one level deep
+		foreach($tree['replies'] as $reply) {
+			$this->assertTrue($reply['comment'] instanceof \OCP\Comments\IComment);
+			$this->assertSame($reply['comment']->getId(), strval($id));
+			$this->assertSame(count($reply['replies']), 0);
+			$id--;
+		}
+	}
+
+	public function testGetTreeNoReplies() {
+		$id = $this->addDatabaseEntry(0, 0);
+
+		$manager = $this->getManager();
+		$tree = $manager->getTree($id);
+
+		// Verifying the root comment
+		$this->assertTrue(isset($tree['comment']));
+		$this->assertTrue($tree['comment'] instanceof \OCP\Comments\IComment);
+		$this->assertSame($tree['comment']->getId(), strval($id));
+		$this->assertTrue(isset($tree['replies']));
+		$this->assertSame(count($tree['replies']), 0);
+
+		// one level deep
+		foreach($tree['replies'] as $reply) {
+			throw new \Exception('This ain`t happen');
+		}
+	}
+
+	public function testGetTreeWithLimitAndOffset() {
+		$headId = $this->addDatabaseEntry(0, 0);
+
+		$this->addDatabaseEntry($headId, $headId, new \DateTime('-3 hours'));
+		$this->addDatabaseEntry($headId, $headId, new \DateTime('-2 hours'));
+		$this->addDatabaseEntry($headId, $headId, new \DateTime('-1 hour'));
+		$idToVerify = $this->addDatabaseEntry($headId, $headId, new \DateTime());
+
+		$manager = $this->getManager();
+
+		for ($offset = 0; $offset < 3; $offset += 2) {
+			$tree = $manager->getTree(strval($headId), 2, $offset);
+
+			// Verifying the root comment
+			$this->assertTrue(isset($tree['comment']));
+			$this->assertTrue($tree['comment'] instanceof \OCP\Comments\IComment);
+			$this->assertSame($tree['comment']->getId(), strval($headId));
+			$this->assertTrue(isset($tree['replies']));
+			$this->assertSame(count($tree['replies']), 2);
+
+			// one level deep
+			foreach ($tree['replies'] as $reply) {
+				$this->assertTrue($reply['comment'] instanceof \OCP\Comments\IComment);
+				$this->assertSame($reply['comment']->getId(), strval($idToVerify));
+				$this->assertSame(count($reply['replies']), 0);
+				$idToVerify--;
+			}
+		}
+	}
+
+	public function testGetForObject() {
+		$this->addDatabaseEntry(0, 0);
+
+		$manager = $this->getManager();
+		$comments = $manager->getForObject('file', 'file64');
+
+		$this->assertTrue(is_array($comments));
+		$this->assertSame(count($comments), 1);
+		$this->assertTrue($comments[0] instanceof \OCP\Comments\IComment);
+		$this->assertSame($comments[0]->getMessage(), 'nice one');
+	}
+
+	public function testGetForObjectWithLimitAndOffset() {
+		$this->addDatabaseEntry(0, 0, new \DateTime('-6 hours'));
+		$this->addDatabaseEntry(0, 0, new \DateTime('-5 hours'));
+		$this->addDatabaseEntry(1, 1, new \DateTime('-4 hours'));
+		$this->addDatabaseEntry(0, 0, new \DateTime('-3 hours'));
+		$this->addDatabaseEntry(2, 2, new \DateTime('-2 hours'));
+		$this->addDatabaseEntry(2, 2, new \DateTime('-1 hours'));
+		$idToVerify = $this->addDatabaseEntry(3, 1, new \DateTime());
+
+		$manager = $this->getManager();
+		$offset = 0;
+		do {
+			$comments = $manager->getForObject('file', 'file64', 3, $offset);
+
+			$this->assertTrue(is_array($comments));
+			foreach($comments as $comment) {
+				$this->assertTrue($comment instanceof \OCP\Comments\IComment);
+				$this->assertSame($comment->getMessage(), 'nice one');
+				$this->assertSame($comment->getId(), strval($idToVerify));
+				$idToVerify--;
+			}
+			$offset += 3;
+		} while(count($comments) > 0);
+	}
+
+	public function testGetForObjectWithDateTimeConstraint() {
+		$this->addDatabaseEntry(0, 0, new \DateTime('-6 hours'));
+		$this->addDatabaseEntry(0, 0, new \DateTime('-5 hours'));
+		$id1 = $this->addDatabaseEntry(0, 0, new \DateTime('-3 hours'));
+		$id2 = $this->addDatabaseEntry(2, 2, new \DateTime('-2 hours'));
+
+		$manager = $this->getManager();
+		$comments = $manager->getForObject('file', 'file64', 0, 0, new \DateTime('-4 hours'));
+
+		$this->assertSame(count($comments), 2);
+		$this->assertSame($comments[0]->getId(), strval($id2));
+		$this->assertSame($comments[1]->getId(), strval($id1));
+	}
+
+	public function testGetForObjectWithLimitAndOffsetAndDateTimeConstraint() {
+		$this->addDatabaseEntry(0, 0, new \DateTime('-7 hours'));
+		$this->addDatabaseEntry(0, 0, new \DateTime('-6 hours'));
+		$this->addDatabaseEntry(1, 1, new \DateTime('-5 hours'));
+		$this->addDatabaseEntry(0, 0, new \DateTime('-3 hours'));
+		$this->addDatabaseEntry(2, 2, new \DateTime('-2 hours'));
+		$this->addDatabaseEntry(2, 2, new \DateTime('-1 hours'));
+		$idToVerify = $this->addDatabaseEntry(3, 1, new \DateTime());
+
+		$manager = $this->getManager();
+		$offset = 0;
+		do {
+			$comments = $manager->getForObject('file', 'file64', 3, $offset, new \DateTime('-4 hours'));
+
+			$this->assertTrue(is_array($comments));
+			foreach($comments as $comment) {
+				$this->assertTrue($comment instanceof \OCP\Comments\IComment);
+				$this->assertSame($comment->getMessage(), 'nice one');
+				$this->assertSame($comment->getId(), strval($idToVerify));
+				$this->assertTrue(intval($comment->getId()) >= 4);
+				$idToVerify--;
+			}
+			$offset += 3;
+		} while(count($comments) > 0);
+	}
+
+	public function testGetNumberOfCommentsForObject() {
+		for($i = 1; $i < 5; $i++) {
+			$this->addDatabaseEntry(0, 0);
+		}
+
+		$manager = $this->getManager();
+
+		$amount = $manager->getNumberOfCommentsForObject('untype', '00');
+		$this->assertSame($amount, 0);
+
+		$amount = $manager->getNumberOfCommentsForObject('file', 'file64');
+		$this->assertSame($amount, 4);
+	}
+
+	public function invalidCreateArgsProvider() {
+		return [
+			['', 'aId-1', 'oType-1', 'oId-1'],
+			['aType-1', '', 'oType-1', 'oId-1'],
+			['aType-1', 'aId-1', '', 'oId-1'],
+			['aType-1', 'aId-1', 'oType-1', ''],
+			[1, 'aId-1', 'oType-1', 'oId-1'],
+			['aType-1', 1, 'oType-1', 'oId-1'],
+			['aType-1', 'aId-1', 1, 'oId-1'],
+			['aType-1', 'aId-1', 'oType-1', 1],
+		];
+	}
+
+	/**
+	 * @dataProvider invalidCreateArgsProvider
+	 */
+	public function testCreateCommentInvalidArguments($aType, $aId, $oType, $oId) {
+		$manager = $this->getManager();
+		$this->setExpectedException('\InvalidArgumentException');
+		$manager->create($aType, $aId, $oType, $oId);
+	}
+
+	public function testCreateComment() {
+		$actorType = 'bot';
+		$actorId = 'bob';
+		$objectType = 'weather';
+		$objectId = 'bielefeld';
+
+		$comment = $this->getManager()->create($actorType, $actorId, $objectType, $objectId);
+		$this->assertTrue($comment instanceof \OCP\Comments\IComment);
+		$this->assertSame($comment->getActorType(), $actorType);
+		$this->assertSame($comment->getActorId(), $actorId);
+		$this->assertSame($comment->getObjectType(), $objectType);
+		$this->assertSame($comment->getObjectId(), $objectId);
+	}
+
+	public function testDelete() {
+		$manager = $this->getManager();
+
+		$done = $manager->delete('404');
+		$this->assertFalse($done);
+
+		$done = $manager->delete('%');
+		$this->assertFalse($done);
+
+		$done = $manager->delete('');
+		$this->assertFalse($done);
+
+		$id = strval($this->addDatabaseEntry(0, 0));
+		$comment = $manager->get($id);
+		$this->assertTrue($comment instanceof \OCP\Comments\IComment);
+		$done = $manager->delete($id);
+		$this->assertTrue($done);
+		$this->setExpectedException('\OCP\Comments\NotFoundException');
+		$manager->get($id);
+	}
+
+	public function testSaveNew() {
+		$manager = $this->getManager();
+		$comment = new \OC\Comments\Comment();
+		$comment
+			->setActor('user', 'alice')
+			->setObject('file', 'file64')
+			->setMessage('very beautiful, I am impressed!')
+			->setVerb('comment');
+
+		$saveSuccessful = $manager->save($comment);
+		$this->assertTrue($saveSuccessful);
+		$this->assertTrue($comment->getId() !== '');
+		$this->assertTrue($comment->getId() !== '0');
+		$this->assertTrue(!is_null($comment->getCreationDateTime()));
+
+		$loadedComment = $manager->get($comment->getId());
+		$this->assertSame($comment->getMessage(), $loadedComment->getMessage());
+		$this->assertEquals($comment->getCreationDateTime(), $loadedComment->getCreationDateTime());
+	}
+
+	public function testSaveUpdate() {
+		$manager = $this->getManager();
+		$comment = new \OC\Comments\Comment();
+		$comment
+				->setActor('user', 'alice')
+				->setObject('file', 'file64')
+				->setMessage('very beautiful, I am impressed!')
+				->setVerb('comment');
+
+		$manager->save($comment);
+
+		$comment->setMessage('very beautiful, I am really so much impressed!');
+		$manager->save($comment);
+
+		$loadedComment = $manager->get($comment->getId());
+		$this->assertSame($comment->getMessage(), $loadedComment->getMessage());
+	}
+
+	public function testSaveUpdateException() {
+		$manager = $this->getManager();
+		$comment = new \OC\Comments\Comment();
+		$comment
+				->setActor('user', 'alice')
+				->setObject('file', 'file64')
+				->setMessage('very beautiful, I am impressed!')
+				->setVerb('comment');
+
+		$manager->save($comment);
+
+		$manager->delete($comment->getId());
+		$comment->setMessage('very beautiful, I am really so much impressed!');
+		$this->setExpectedException('\OCP\Comments\NotFoundException');
+		$manager->save($comment);
+	}
+
+	public function testSaveIncomplete() {
+		$manager = $this->getManager();
+		$comment = new \OC\Comments\Comment();
+		$comment->setMessage('from no one to nothing');
+		$this->setExpectedException('\UnexpectedValueException');
+		$manager->save($comment);
+	}
+
+	public function testSaveAsChild() {
+		$id = $this->addDatabaseEntry(0, 0);
+
+		$manager = $this->getManager();
+
+		for($i = 0; $i < 3; $i++) {
+			$comment = new \OC\Comments\Comment();
+			$comment
+					->setActor('user', 'alice')
+					->setObject('file', 'file64')
+					->setParentId(strval($id))
+					->setMessage('full ack')
+					->setVerb('comment')
+					// setting the creation time avoids using sleep() while making sure to test with different timestamps
+					->setCreationDateTime(new \DateTime('+' . $i . ' minutes'));
+
+			$manager->save($comment);
+
+			$this->assertSame($comment->getTopmostParentId(), strval($id));
+			$parentComment = $manager->get(strval($id));
+			$this->assertSame($parentComment->getChildrenCount(), $i + 1);
+			$this->assertEquals($parentComment->getLatestChildDateTime(), $comment->getCreationDateTime());
+		}
+	}
+
+	public function invalidActorArgsProvider() {
+		return
+		[
+			['', ''],
+			[1, 'alice'],
+			['user', 1],
+		];
+	}
+
+	/**
+	 * @dataProvider invalidActorArgsProvider
+	 */
+	public function testDeleteReferencesOfActorInvalidInput($type, $id) {
+		$manager = $this->getManager();
+		$this->setExpectedException('\InvalidArgumentException');
+		$manager->deleteReferencesOfActor($type, $id);
+	}
+
+	public function testDeleteReferencesOfActor() {
+		$ids = [];
+		$ids[] = $this->addDatabaseEntry(0, 0);
+		$ids[] = $this->addDatabaseEntry(0, 0);
+		$ids[] = $this->addDatabaseEntry(0, 0);
+
+		$manager = $this->getManager();
+
+		// just to make sure they are really set, with correct actor data
+		$comment = $manager->get(strval($ids[1]));
+		$this->assertSame($comment->getActorType(), 'user');
+		$this->assertSame($comment->getActorId(), 'alice');
+
+		$wasSuccessful = $manager->deleteReferencesOfActor('user', 'alice');
+		$this->assertTrue($wasSuccessful);
+
+		foreach($ids as $id) {
+			$comment = $manager->get(strval($id));
+			$this->assertSame($comment->getActorType(), ICommentsManager::DELETED_USER);
+			$this->assertSame($comment->getActorId(), ICommentsManager::DELETED_USER);
+		}
+
+		// actor info is gone from DB, but when database interaction is alright,
+		// we still expect to get true back
+		$wasSuccessful = $manager->deleteReferencesOfActor('user', 'alice');
+		$this->assertTrue($wasSuccessful);
+	}
+
+	public function testDeleteReferencesOfActorWithUserManagement() {
+		$user = \oc::$server->getUserManager()->createUser('xenia', '123456');
+		$this->assertTrue($user instanceof \OCP\IUser);
+
+		$manager = $this->getManager();
+		$comment = $manager->create('user', $user->getUID(), 'file', 'file64');
+		$comment
+			->setMessage('Most important comment I ever left on the Internet.')
+			->setVerb('comment');
+		$status = $manager->save($comment);
+		$this->assertTrue($status);
+
+		$commentID = $comment->getId();
+		$user->delete();
+
+		$comment =$manager->get($commentID);
+		$this->assertSame($comment->getActorType(), \OCP\Comments\ICommentsManager::DELETED_USER);
+		$this->assertSame($comment->getActorId(), \OCP\Comments\ICommentsManager::DELETED_USER);
+	}
+
+	public function invalidObjectArgsProvider() {
+		return
+				[
+						['', ''],
+						[1, 'file64'],
+						['file', 1],
+				];
+	}
+
+	/**
+	 * @dataProvider invalidObjectArgsProvider
+	 */
+	public function testDeleteCommentsAtObjectInvalidInput($type, $id) {
+		$manager = $this->getManager();
+		$this->setExpectedException('\InvalidArgumentException');
+		$manager->deleteCommentsAtObject($type, $id);
+	}
+
+	public function testDeleteCommentsAtObject() {
+		$ids = [];
+		$ids[] = $this->addDatabaseEntry(0, 0);
+		$ids[] = $this->addDatabaseEntry(0, 0);
+		$ids[] = $this->addDatabaseEntry(0, 0);
+
+		$manager = $this->getManager();
+
+		// just to make sure they are really set, with correct actor data
+		$comment = $manager->get(strval($ids[1]));
+		$this->assertSame($comment->getObjectType(), 'file');
+		$this->assertSame($comment->getObjectId(), 'file64');
+
+		$wasSuccessful = $manager->deleteCommentsAtObject('file', 'file64');
+		$this->assertTrue($wasSuccessful);
+
+		$verified = 0;
+		foreach($ids as $id) {
+			try {
+				$manager->get(strval($id));
+			} catch (\OCP\Comments\NotFoundException $e) {
+				$verified++;
+			}
+		}
+		$this->assertSame($verified, 3);
+
+		// actor info is gone from DB, but when database interaction is alright,
+		// we still expect to get true back
+		$wasSuccessful = $manager->deleteCommentsAtObject('file', 'file64');
+		$this->assertTrue($wasSuccessful);
+	}
+
+	public function testOverwriteDefaultManager() {
+		$config = \oc::$server->getConfig();
+		$defaultManagerFactory = $config->getSystemValue('comments.managerFactory', '\OC\Comments\ManagerFactory');
+
+		$managerMock = $this->getMock('\OCP\Comments\ICommentsManager');
+
+		$config->setSystemValue('comments.managerFactory', 'Test_Comments_FakeFactory');
+		$manager = \oc::$server->getCommentsManager();
+		$this->assertEquals($managerMock, $manager);
+
+		$config->setSystemValue('comments.managerFactory', $defaultManagerFactory);
+	}
+
+}
diff --git a/tests/lib/server.php b/tests/lib/server.php
index b72bef82036..0bee19822d2 100644
--- a/tests/lib/server.php
+++ b/tests/lib/server.php
@@ -61,6 +61,7 @@ class Server extends \Test\TestCase {
 			['CapabilitiesManager', '\OC\CapabilitiesManager'],
 			['ContactsManager', '\OC\ContactsManager'],
 			['ContactsManager', '\OCP\Contacts\IManager'],
+			['CommentsManager', '\OCP\Comments\ICommentsManager'],
 			['Crypto', '\OC\Security\Crypto'],
 			['Crypto', '\OCP\Security\ICrypto'],
 			['CryptoWrapper', '\OC\Session\CryptoWrapper'],