chore: Add Commits to Repository Mock's compare result

NGitLab.Mock.Tests/RepositoryMockTests.cs

@@ -1,4 +1,6 @@
-using NGitLab.Models;
+using System.Linq;
+using System.Threading.Tasks;
+using NGitLab.Models;
 using NUnit.Framework;
 
 namespace NGitLab.Mock.Tests;
@@ -219,4 +221,51 @@ public void Test_create_a_new_commit_on_existing_branch()
         });
         Assert.That(newCommit.Message.Trim(), Is.EqualTo(commitMessage));
     }
+
+    [Test]
+    public async Task Test_commit_diff_returns_diff_information()
+    {
+        // Arrange
+        using var server = new GitLabServer();
+        var user = server.Users.AddNew();
+        var project = user.Namespace.Projects.AddNew(project => project.Visibility = VisibilityLevel.Internal);
+        var initCommit = project.Repository.Commit(user, "Initial commit");
+
+        var mainCommit = project.Repository.Commit(user, "Main commit");
+
+        project.Repository.CreateAndCheckoutBranch("to-be-merged");
+        project.Repository.Commit(user, "branch commit");
+        var mr = project.CreateMergeRequest(user, "Merge request commit", "mr description", project.DefaultBranch, "to-be-merged");
+        mr.Accept(user);
+
+        // Act
+        var client = server.CreateClient(user);
+        var diff = await client.GetRepository(project.Id).CompareAsync(new(initCommit.Sha, mr.MergeCommitSha!.ToString()));
+
+        using (Assert.EnterMultipleScope())
+        {
+            // Assert
+            Assert.That(diff.Diff, Is.Not.Empty);
+            Assert.That(diff.Commits.Select(c => c.Id), Is.EqualTo([new Sha1(mainCommit.Sha), mr.MergeCommitSha]));
+            Assert.That(diff.Commit?.Id, Is.EqualTo(mr.MergeCommitSha));
+        }
+    }
+
+    [Test]
+    public async Task Test_commit_diff_same_commit_returns_empty_diff()
+    {
+        // Arrange
+        using var server = new GitLabServer();
+        var user = server.Users.AddNew();
+        var project = user.Namespace.Projects.AddNew(project => project.Visibility = VisibilityLevel.Internal);
+        var initCommit = project.Repository.Commit(user, "Initial commit");
+
+        // Act & assert
+        var client = server.CreateClient(user);
+        var diff = await client.GetRepository(project.Id).CompareAsync(new(initCommit.Sha, initCommit.Sha));
+
+        Assert.That(diff.Diff, Is.Empty);
+        Assert.That(diff.Commits, Is.Empty);
+        Assert.That(diff.Commit, Is.Null);
+    }
 }

NGitLab.Mock/Clients/RepositoryClient.cs

@@ -150,6 +150,11 @@ private CompareResults CompareLockless(CompareQuery query)
     {
         var project = GetProject(_projectId, ProjectPermission.View);
         var treeChanges = project.Repository.Compare(query.From, query.To);
+        var commits = project.Repository.GetCommits($"{query.From}..{query.To}")
+            .Select(c => c.ToCommitClient(project))
+            .Reverse()
+            .ToArray();
+
         return new CompareResults()
         {
             Diff = treeChanges.Select(change
@@ -161,6 +166,8 @@ private CompareResults CompareLockless(CompareQuery query)
                     IsDeletedFile = change.Status is ChangeKind.Deleted,
                     IsRenamedFile = change.Status is ChangeKind.Renamed,
                 }).ToArray(),
+            Commit = commits.LastOrDefault(),
+            Commits = commits,
         };
     }