Organization membership preview API changes - Review user permission (#1633)

* Add organization membership preview header

* Add API endpoints to preview a collaborators permission

* Add methods to preview a collaborators permission

* Add methods to the observable repo collaborator client

* Fix convention test failure

* Use correct API endpoint when using repository ID

* Move the helper function pair so they aren't in between another pair

* Use the correct URL for the review permission API endpoint

* Add unit tests

* Add integration tests for review permission methods

* Fix spelling mistake

* Renaming enum as per review

Octokit.Reactive/Clients/IObservableRepoCollaboratorsClient.cs

@@ -78,6 +78,29 @@ namespace Octokit.Reactive
         /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
         IObservable<bool> IsCollaborator(long repositoryId, string user);
 
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        IObservable<CollaboratorPermission> ReviewPermission(string owner, string name, string user);
+
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="repositoryId">The id of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        IObservable<CollaboratorPermission> ReviewPermission(long repositoryId, string user);
+
         /// <summary>
         /// Adds a new collaborator to the repository.
         /// </summary>

Octokit.Reactive/Clients/ObservableRepoCollaboratorsClient.cs

@@ -128,6 +128,41 @@ namespace Octokit.Reactive
             return _client.IsCollaborator(repositoryId, user).ToObservable();
         }
 
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        public IObservable<CollaboratorPermission> ReviewPermission(string owner, string name, string user)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+            Ensure.ArgumentNotNullOrEmptyString(name, "name");
+            Ensure.ArgumentNotNullOrEmptyString(user, "user");
+
+            return _client.ReviewPermission(owner, name, user).ToObservable();
+        }
+
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="repositoryId">The id of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        public IObservable<CollaboratorPermission> ReviewPermission(long repositoryId, string user)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(user, "user");
+
+            return _client.ReviewPermission(repositoryId, user).ToObservable();
+        }
+
         /// <summary>
         /// Adds a new collaborator to the repository.
         /// </summary>

Octokit.Tests.Integration/Clients/RepositoryCollaboratorClientTests.cs

@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System;
+using System.Threading.Tasks;
 using Octokit;
 using Octokit.Tests.Integration;
 using Xunit;
@@ -260,6 +261,153 @@ public class RepositoryCollaboratorClientTests
         }
     }
 
+    public class TheReviewPermissionMethod
+    {
+        [IntegrationTest]
+        public async Task ReturnsReadPermissionForNonCollaborator()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Read, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsReadPermissionForNonCollaboratorWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Read, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsWritePermissionForCollaborator()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                // add a collaborator
+                await fixture.Add(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Write, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsWritePermissionForCollaboratorWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                // add a collaborator
+                await fixture.Add(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Write, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsAdminPermissionForOwner()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, context.RepositoryOwner);
+
+                Assert.Equal(PermissionLevel.Admin, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsAdminPermissionForOwnerWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, context.RepositoryOwner);
+
+                Assert.Equal(PermissionLevel.Admin, permission.Permission);
+            }
+        }
+
+        [PaidAccountTest]
+        public async Task ReturnsNonePermissionForPrivateRepository()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var userDetails = await github.User.Current();
+            if (userDetails.Plan.PrivateRepos == 0)
+            {
+                throw new Exception("Test cannot complete, account is on free plan");
+            }
+
+            var repoName = Helper.MakeNameWithTimestamp("private-repo");
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName) { Private = true }))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+ 
+                Assert.Equal(PermissionLevel.None, permission.Permission);
+            }
+        }
+
+        [PaidAccountTest]
+        public async Task ReturnsNonePermissionForPrivateRepositoryWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var userDetails = await github.User.Current();
+            if (userDetails.Plan.PrivateRepos == 0)
+            {
+                throw new Exception("Test cannot complete, account is on free plan");
+            }
+
+            var repoName = Helper.MakeNameWithTimestamp("private-repo");
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName) { Private = true }))
+            {
+                var fixture = github.Repository.Collaborator;
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.None, permission.Permission);
+            }
+        }
+    }
+
     public class TheDeleteMethod
     {
         [IntegrationTest]

Octokit.Tests.Integration/Reactive/ObservableRepositoryCollaboratorClientTests.cs

@@ -1,4 +1,5 @@
-using System.Reactive.Linq;
+using System;
+using System.Reactive.Linq;
 using System.Threading.Tasks;
 using Octokit;
 using Octokit.Reactive;
@@ -138,4 +139,151 @@ public class ObservableRepositoryCollaboratorClientTests
             }
         }
     }
+    public class TheReviewPermissionMethod
+    {
+
+        [IntegrationTest]
+        public async Task ReturnsReadPermissionForNonCollaborator()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Read, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsReadPermissionForNonCollaboratorWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Read, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsWritePermissionForCollaborator()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                // add a collaborator
+                await fixture.Add(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Write, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsWritePermissionForCollaboratorWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                // add a collaborator
+                await fixture.Add(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.Write, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsAdminPermissionForOwner()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, context.RepositoryOwner);
+
+                Assert.Equal(PermissionLevel.Admin, permission.Permission);
+            }
+        }
+
+        [IntegrationTest]
+        public async Task ReturnsAdminPermissionForOwnerWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var repoName = Helper.MakeNameWithTimestamp("public-repo");
+
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName)))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, context.RepositoryOwner);
+
+                Assert.Equal(PermissionLevel.Admin, permission.Permission);
+            }
+        }
+
+        [PaidAccountTest]
+        public async Task ReturnsNonePermissionForPrivateRepository()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var userDetails = await github.User.Current();
+            if (userDetails.Plan.PrivateRepos == 0)
+            {
+                throw new Exception("Test cannot complete, account is on free plan");
+            }
+
+            var repoName = Helper.MakeNameWithTimestamp("private-repo");
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName) { Private = true }))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                var permission = await fixture.ReviewPermission(context.RepositoryOwner, context.RepositoryName, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.None, permission.Permission);
+            }
+        }
+
+        [PaidAccountTest]
+        public async Task ReturnsNonePermissionForPrivateRepositoryWithRepositoryId()
+        {
+            var github = Helper.GetAuthenticatedClient();
+            var userDetails = await github.User.Current();
+            if (userDetails.Plan.PrivateRepos == 0)
+            {
+                throw new Exception("Test cannot complete, account is on free plan");
+            }
+
+            var repoName = Helper.MakeNameWithTimestamp("private-repo");
+            using (var context = await github.CreateRepositoryContext(new NewRepository(repoName) { Private = true }))
+            {
+                var fixture = new ObservableRepoCollaboratorsClient(github);
+
+                var permission = await fixture.ReviewPermission(context.RepositoryId, "alfhenrik-test-2");
+
+                Assert.Equal(PermissionLevel.None, permission.Permission);
+            }
+        }
+    }
 }

Octokit.Tests/Clients/RepoCollaboratorsClientTests.cs

@@ -190,6 +190,52 @@ namespace Octokit.Tests.Clients
             }
         }
 
+        public class TheReviewPermissionMethod
+        {
+            [Fact]
+            public void RequestsCorrectUrl()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new RepoCollaboratorsClient(connection);
+
+                client.ReviewPermission("owner", "test", "user1");
+                connection.Received().Get<CollaboratorPermission>(
+                    Arg.Is<Uri>(u => u.ToString() == "repos/owner/test/collaborators/user1/permission"),
+                    Arg.Any<Dictionary<string, string>>(), 
+                    "application/vnd.github.korra-preview+json");
+            }
+
+            [Fact]
+            public void RequestsCorrectUrlWithRepositoryId()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new RepoCollaboratorsClient(connection);
+
+                client.ReviewPermission(1L, "user1");
+                connection.Received().Get<CollaboratorPermission>(
+                    Arg.Is<Uri>(u => u.ToString() == "repositories/1/collaborators/user1/permission"),
+                    Arg.Any<Dictionary<string, string>>(), 
+                    "application/vnd.github.korra-preview+json");
+            }
+
+            [Fact]
+            public async Task EnsuresNonNullArguments()
+            {
+                var client = new RepoCollaboratorsClient(Substitute.For<IApiConnection>());
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.ReviewPermission(null, "test", "user1"));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.ReviewPermission("", "test", "user1"));
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.ReviewPermission("owner", null, "user1"));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.ReviewPermission("owner", "", "user1"));
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.ReviewPermission("owner", "test", null));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.ReviewPermission("owner", "test", ""));
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.ReviewPermission(1L, null));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.ReviewPermission(1L, ""));
+            }
+
+        }
+
         public class TheAddMethod
         {
             [Fact]

Octokit.Tests/Reactive/ObservableRepoCollaboratorsClientTests.cs

@@ -253,6 +253,92 @@ namespace Octokit.Tests.Reactive
             }
         }
 
+        public class TheReviewPermissionMethod
+        {
+            private readonly IGitHubClient _gitHubClient;
+            private IObservableRepoCollaboratorsClient _client;
+
+            public TheReviewPermissionMethod()
+            {
+                _gitHubClient = Substitute.For<IGitHubClient>();
+            }
+
+            private void SetupWithoutNonReactiveClient()
+            {
+                _client = new ObservableRepoCollaboratorsClient(_gitHubClient);
+            }
+
+            private void SetupWithNonReactiveClient()
+            {
+                var collaboratorsClient = new RepoCollaboratorsClient(Substitute.For<IApiConnection>());
+                _gitHubClient.Repository.Collaborator.Returns(collaboratorsClient);
+                _client = new ObservableRepoCollaboratorsClient(_gitHubClient);
+            }
+
+            [Fact]
+            public void EnsuresNonNullArguments()
+            {
+                SetupWithNonReactiveClient();
+
+                Assert.Throws<ArgumentNullException>(() => _client.ReviewPermission(null, "test", "user1"));
+                Assert.Throws<ArgumentNullException>(() => _client.ReviewPermission("owner", null, "user1"));
+                Assert.Throws<ArgumentNullException>(() => _client.ReviewPermission("owner", "test", null));
+                Assert.Throws<ArgumentNullException>(() => _client.ReviewPermission(1L, null));
+            }
+
+            [Fact]
+            public void EnsuresNonEmptyArguments()
+            {
+                SetupWithNonReactiveClient();
+
+                Assert.Throws<ArgumentException>(() => _client.ReviewPermission("", "test", "user1"));
+                Assert.Throws<ArgumentException>(() => _client.ReviewPermission("owner", "", "user1"));
+                Assert.Throws<ArgumentException>(() => _client.ReviewPermission("owner", "test", ""));
+                Assert.Throws<ArgumentException>(() => _client.ReviewPermission(1L, ""));
+            }
+
+            [Fact]
+            public async Task EnsuresNonWhitespaceArguments()
+            {
+                SetupWithNonReactiveClient();
+
+                await AssertEx.ThrowsWhenGivenWhitespaceArgument(
+                    async whitespace => await _client.ReviewPermission(whitespace, "repo", "user"));
+                await AssertEx.ThrowsWhenGivenWhitespaceArgument(
+                    async whitespace => await _client.ReviewPermission("owner", whitespace, "user"));
+                await AssertEx.ThrowsWhenGivenWhitespaceArgument(
+                    async whitespace => await _client.ReviewPermission("owner", "repo", whitespace));
+                await AssertEx.ThrowsWhenGivenWhitespaceArgument(
+                    async whitespace => await _client.ReviewPermission(1L, whitespace));
+            }
+
+            [Fact]
+            public void CallsReviewPermissionOnRegularRepoCollaboratorsClient()
+            {
+                SetupWithoutNonReactiveClient();
+
+                _client.ReviewPermission("owner", "repo", "user");
+
+                _gitHubClient.Repository.Collaborator.Received(1).ReviewPermission(
+                    Arg.Is("owner"),
+                    Arg.Is("repo"),
+                    Arg.Is("user"));
+            }
+
+            [Fact]
+            public void CallsReviewPermissionOnRegularRepoCollaboratorsClientWithRepositoryId()
+            {
+                SetupWithoutNonReactiveClient();
+
+                var id = 1L;
+                _client.ReviewPermission(id, "user");
+
+                _gitHubClient.Repository.Collaborator.Received(1).ReviewPermission(
+                    Arg.Is(id),
+                    Arg.Is("user"));
+            }
+        }
+
         public class TheAddMethod
         {
             private readonly IGitHubClient _githubClient;

Octokit/Clients/IRepoCollaboratorsClient.cs

@@ -78,6 +78,29 @@ namespace Octokit
         /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
         Task<bool> IsCollaborator(long repositoryId, string user);
 
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        Task<CollaboratorPermission> ReviewPermission(string owner, string name, string user);
+
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="repositoryId">The id of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        Task<CollaboratorPermission> ReviewPermission(long repositoryId, string user);
+
         /// <summary>
         /// Adds a new collaborator to the repository.
         /// </summary>

Octokit/Clients/RepoCollaboratorsClient.cs

@@ -136,6 +136,43 @@ namespace Octokit
             }
         }
 
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        public Task<CollaboratorPermission> ReviewPermission(string owner, string name, string user)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
+            Ensure.ArgumentNotNullOrEmptyString(name, "name");
+            Ensure.ArgumentNotNullOrEmptyString(user, "user");
+
+            return ApiConnection
+                .Get<CollaboratorPermission>(ApiUrls.RepoCollaboratorPermission(owner, name, user), null, AcceptHeaders.OrganizationMembershipPreview);
+        }
+
+        /// <summary>
+        /// Review a user's permission level in a repository
+        /// </summary>
+        /// <remarks>
+        /// See the <a href="https://developer.github.com/v3/repos/collaborators/#review-a-users-permission-level">API documentation</a> for more information.
+        /// </remarks>
+        /// <param name="repositoryId">The id of the repository</param>
+        /// <param name="user">Username of the collaborator to check permission for</param>
+        /// <exception cref="ApiException">Thrown when a general API error occurs.</exception>
+        public Task<CollaboratorPermission> ReviewPermission(long repositoryId, string user)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(user, "user");
+
+            return ApiConnection
+                .Get<CollaboratorPermission>(ApiUrls.RepoCollaboratorPermission(repositoryId, user), null, AcceptHeaders.OrganizationMembershipPreview);
+        }
+        
         /// <summary>
         /// Adds a new collaborator to the repository.
         /// </summary>

Octokit/Helpers/AcceptHeaders.cs

@@ -46,5 +46,8 @@ namespace Octokit
         public const string PullRequestReviewsApiPreview = "application/vnd.github.black-cat-preview+json";
 
         public const string ProjectsApiPreview = "application/vnd.github.inertia-preview+json";
+
+        public const string OrganizationMembershipPreview = "application/vnd.github.korra-preview+json";
+
     }
 }

Octokit/Helpers/ApiUrls.cs

@@ -1518,6 +1518,23 @@ namespace Octokit
             return "repositories/{0}/collaborators/{1}".FormatUri(repositoryId, user);
         }
 
+        /// <summary>
+        /// Returns the <see cref="Uri"/> to review the collaborators permission
+        /// </summary>
+        /// <param name="owner">The owner of the repo</param>
+        /// <param name="repo">The name of the repo</param>
+        /// <param name="user">The name of the user</param>
+        /// <returns>The <see cref="Uri"/> to review the collaborators permission</returns>
+        public static Uri RepoCollaboratorPermission(string owner, string repo, string user)
+        {
+            return "repos/{0}/{1}/collaborators/{2}/permission".FormatUri(owner, repo, user);
+        }
+
+        public static Uri RepoCollaboratorPermission(long repositoryId, string user)
+        {
+            return "repositories/{0}/collaborators/{1}/permission".FormatUri(repositoryId, user);
+        }
+
         /// <summary>
         /// returns the <see cref="Uri"/> for branches
         /// </summary>

Octokit/Models/Response/CollaboratorPermission.cs

@@ -0,0 +1,13 @@
+using System.Diagnostics;
+
+namespace Octokit
+{
+    [DebuggerDisplay("{DebuggerDisplay,nq}")]
+    public class CollaboratorPermission
+    {
+        public StringEnum<PermissionLevel> Permission { get; protected set; }
+        public User User { get; protected set; }
+
+        internal string DebuggerDisplay => $"User: {User.Id} Permission: {Permission}";
+    }
+}

Octokit/Models/Response/PermissionLevel.cs

@@ -0,0 +1,16 @@
+using Octokit.Internal;
+
+namespace Octokit
+{
+    public enum PermissionLevel
+    {
+        [Parameter(Value = "admin")]
+        Admin,
+        [Parameter(Value = "write")]
+        Write,
+        [Parameter(Value = "read")]
+        Read,
+        [Parameter(Value = "none")]
+        None
+    }
+}