Add API to query collaborators permission for a repository (#18761)

Targeting #14936, #15332

Adds a collaborator permissions API endpoint according to GitHub API: https://docs.github.com/en/rest/collaborators/collaborators#get-repository-permissions-for-a-user to retrieve a collaborators permissions for a specific repository.

### Checks the repository permissions of a collaborator. 

`GET` `/repos/{owner}/{repo}/collaborators/{collaborator}/permission`

Possible `permission` values are `admin`, `write`, `read`, `owner`, `none`.

```json
{
  "permission": "admin",
  "role_name": "admin",
  "user": {}
}
```

Where `permission` and `role_name` hold the same `permission` value and `user` is filled with the user API object. Only admins are allowed to use this API endpoint.

1 files changed, 131 insertions, 0 deletions

diff --git a/integrations/api_repo_collaborator_test.go b/integrations/api_repo_collaborator_test.go
new file mode 100644
index 0000000000..fdca1d9150
--- /dev/null
+++ b/integrations/api_repo_collaborator_test.go
@@ -0,0 +1,131 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package integrations
+
+import (
+	"net/http"
+	"net/url"
+	"testing"
+
+	"code.gitea.io/gitea/models/perm"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	api "code.gitea.io/gitea/modules/structs"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAPIRepoCollaboratorPermission(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, u *url.URL) {
+		repo2 := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2}).(*repo_model.Repository)
+		repo2Owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo2.OwnerID}).(*user_model.User)
+
+		user4 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 4}).(*user_model.User)
+		user5 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5}).(*user_model.User)
+		user10 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 10}).(*user_model.User)
+		user11 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 11}).(*user_model.User)
+
+		session := loginUser(t, repo2Owner.Name)
+		testCtx := NewAPITestContext(t, repo2Owner.Name, repo2.Name)
+
+		t.Run("RepoOwnerShouldBeOwner", func(t *testing.T) {
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, repo2Owner.Name, testCtx.Token)
+			resp := session.MakeRequest(t, req, http.StatusOK)
+
+			var repoPermission api.RepoCollaboratorPermission
+			DecodeJSON(t, resp, &repoPermission)
+
+			assert.Equal(t, "owner", repoPermission.Permission)
+		})
+
+		t.Run("CollaboratorWithReadAccess", func(t *testing.T) {
+			t.Run("AddUserAsCollaboratorWithReadAccess", doAPIAddCollaborator(testCtx, user4.Name, perm.AccessModeRead))
+
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, user4.Name, testCtx.Token)
+			resp := session.MakeRequest(t, req, http.StatusOK)
+
+			var repoPermission api.RepoCollaboratorPermission
+			DecodeJSON(t, resp, &repoPermission)
+
+			assert.Equal(t, "read", repoPermission.Permission)
+		})
+
+		t.Run("CollaboratorWithWriteAccess", func(t *testing.T) {
+			t.Run("AddUserAsCollaboratorWithWriteAccess", doAPIAddCollaborator(testCtx, user4.Name, perm.AccessModeWrite))
+
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, user4.Name, testCtx.Token)
+			resp := session.MakeRequest(t, req, http.StatusOK)
+
+			var repoPermission api.RepoCollaboratorPermission
+			DecodeJSON(t, resp, &repoPermission)
+
+			assert.Equal(t, "write", repoPermission.Permission)
+		})
+
+		t.Run("CollaboratorWithAdminAccess", func(t *testing.T) {
+			t.Run("AddUserAsCollaboratorWithAdminAccess", doAPIAddCollaborator(testCtx, user4.Name, perm.AccessModeAdmin))
+
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, user4.Name, testCtx.Token)
+			resp := session.MakeRequest(t, req, http.StatusOK)
+
+			var repoPermission api.RepoCollaboratorPermission
+			DecodeJSON(t, resp, &repoPermission)
+
+			assert.Equal(t, "admin", repoPermission.Permission)
+		})
+
+		t.Run("CollaboratorNotFound", func(t *testing.T) {
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, "non-existent-user", testCtx.Token)
+			session.MakeRequest(t, req, http.StatusNotFound)
+		})
+
+		t.Run("CollaboratorCanQueryItsPermissions", func(t *testing.T) {
+			t.Run("AddUserAsCollaboratorWithReadAccess", doAPIAddCollaborator(testCtx, user5.Name, perm.AccessModeRead))
+
+			_session := loginUser(t, user5.Name)
+			_testCtx := NewAPITestContext(t, user5.Name, repo2.Name)
+
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, user5.Name, _testCtx.Token)
+			resp := _session.MakeRequest(t, req, http.StatusOK)
+
+			var repoPermission api.RepoCollaboratorPermission
+			DecodeJSON(t, resp, &repoPermission)
+
+			assert.Equal(t, "read", repoPermission.Permission)
+		})
+
+		t.Run("CollaboratorCanQueryItsPermissions", func(t *testing.T) {
+			t.Run("AddUserAsCollaboratorWithReadAccess", doAPIAddCollaborator(testCtx, user5.Name, perm.AccessModeRead))
+
+			_session := loginUser(t, user5.Name)
+			_testCtx := NewAPITestContext(t, user5.Name, repo2.Name)
+
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, user5.Name, _testCtx.Token)
+			resp := _session.MakeRequest(t, req, http.StatusOK)
+
+			var repoPermission api.RepoCollaboratorPermission
+			DecodeJSON(t, resp, &repoPermission)
+
+			assert.Equal(t, "read", repoPermission.Permission)
+		})
+
+		t.Run("RepoAdminCanQueryACollaboratorsPermissions", func(t *testing.T) {
+			t.Run("AddUserAsCollaboratorWithAdminAccess", doAPIAddCollaborator(testCtx, user10.Name, perm.AccessModeAdmin))
+			t.Run("AddUserAsCollaboratorWithReadAccess", doAPIAddCollaborator(testCtx, user11.Name, perm.AccessModeRead))
+
+			_session := loginUser(t, user10.Name)
+			_testCtx := NewAPITestContext(t, user10.Name, repo2.Name)
+
+			req := NewRequestf(t, "GET", "/api/v1/repos/%s/%s/collaborators/%s/permission?token=%s", repo2Owner.Name, repo2.Name, user11.Name, _testCtx.Token)
+			resp := _session.MakeRequest(t, req, http.StatusOK)
+
+			var repoPermission api.RepoCollaboratorPermission
+			DecodeJSON(t, resp, &repoPermission)
+
+			assert.Equal(t, "read", repoPermission.Permission)
+		})
+	})
+}