add support for retrieving the diffs from a commit (#119)

Author: nainslie

src/GitLabApiClient/CommitsClient.cs

@@ -62,5 +62,17 @@ public async Task<IList<CommitRef>> GetRefsAsync(ProjectId projectId, string sha
             string url = _commitRefsQueryBuilder.Build($"projects/{projectId}/repository/commits/{sha}/refs", queryOptions);
             return await _httpFacade.GetPagedList<CommitRef>(url);
         }
+
+        /// <summary>
+        /// Retrieve a list of differences in this commit
+        /// </summary>
+        /// <param name="projectId">The ID, path or <see cref="Project"/> of the project.</param>
+        /// <param name="sha">The commit hash or name of a repository branch or tag</param>
+        /// <returns></returns>
+        public async Task<IList<Diff>> GetDiffsAsync(ProjectId projectId, string sha)
+        {
+            string url = $"projects/{projectId}/repository/commits/{sha}/diff";
+            return await _httpFacade.GetPagedList<Diff>(url);
+        }
     }
 }

src/GitLabApiClient/Models/Commits/Responses/Diff.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using GitLabApiClient.Models.Releases.Responses;
+using Newtonsoft.Json;
+
+namespace GitLabApiClient.Models.Commits.Responses
+{
+    public sealed class Diff
+    {
+        [JsonProperty("diff")]
+        public string DiffText { get; set; }
+
+        [JsonProperty("new_path")]
+        public string NewPath { get; set; }
+
+        [JsonProperty("old_path")]
+        public string OldPath { get; set; }
+
+        [JsonProperty("a_mode")]
+        public string AMode { get; set; }
+
+        [JsonProperty("b_mode")]
+        public string BMode { get; set; }
+
+        [JsonProperty("new_file")]
+        public bool IsNewFile { get; set; }
+
+        [JsonProperty("renamed_file")]
+        public bool IsRenamedFile { get; set; }
+
+        [JsonProperty("deleted_file")]
+        public bool IsDeletedFile { get; set; }
+    }
+}

test/GitLabApiClient.Test/CommitsClientTest.cs

@@ -60,5 +60,44 @@ public async void GetCommitsByRefName()
             }
 
         }
+
+        [Fact]
+        public async void GetDiffsForCommit()
+        {
+            string gitlabServer = "http://fake-gitlab.com/";
+            string projectId = "id";
+            string sha = "6104942438c14ec7bd21c6cd5bd995272b3faff6";
+            string url = $"/projects/id/repository/commits/{sha}/diff?per_page=100&page=1";
+
+            var handler = A.Fake<MockHandler>(opt => opt.CallsBaseMethods());
+            A.CallTo(() => handler.SendAsync(HttpMethod.Get, url))
+                .ReturnsLazily(() => HttpResponseMessageProducer.Success(
+                    $"[  {{ \"diff\": \"diff1\", \"new_path\": \"new_path1\", \"old_path\": \"old_path1\", \"a_mode\": \"a_mode1\", \"b_mode\": \"b_mode1\", \"new_file\": \"true\", \"renamed_file\": \"false\", \"deleted_file\": \"false\" }},\n  {{\"diff\": \"diff2\", \"new_path\": \"new_path2\", \"old_path\": \"old_path2\", \"a_mode\": \"a_mode2\", \"b_mode\": \"b_mode2\", \"new_file\": \"false\", \"renamed_file\": \"true\", \"deleted_file\": \"true\"}}]"));
+            using (var client = new HttpClient(handler) { BaseAddress = new Uri(gitlabServer) })
+            {
+                var gitlabHttpFacade = new GitLabHttpFacade(new RequestsJsonSerializer(), client);
+                var commitsClient = new CommitsClient(gitlabHttpFacade, new CommitQueryBuilder(), new CommitRefsQueryBuilder());
+
+                var diffsFromClient = await commitsClient.GetDiffsAsync(projectId, sha);
+                diffsFromClient[0].DiffText.Should().BeEquivalentTo("diff1");
+                diffsFromClient[0].NewPath.Should().BeEquivalentTo("new_path1");
+                diffsFromClient[0].OldPath.Should().BeEquivalentTo("old_path1");
+                diffsFromClient[0].AMode.Should().BeEquivalentTo("a_mode1");
+                diffsFromClient[0].BMode.Should().BeEquivalentTo("b_mode1");
+                diffsFromClient[0].IsNewFile.Should().BeTrue();
+                diffsFromClient[0].IsRenamedFile.Should().BeFalse();
+                diffsFromClient[0].IsDeletedFile.Should().BeFalse();
+
+                diffsFromClient[1].DiffText.Should().BeEquivalentTo("diff2");
+                diffsFromClient[1].NewPath.Should().BeEquivalentTo("new_path2");
+                diffsFromClient[1].OldPath.Should().BeEquivalentTo("old_path2");
+                diffsFromClient[1].AMode.Should().BeEquivalentTo("a_mode2");
+                diffsFromClient[1].BMode.Should().BeEquivalentTo("b_mode2");
+                diffsFromClient[1].IsNewFile.Should().BeFalse();
+                diffsFromClient[1].IsRenamedFile.Should().BeTrue();
+                diffsFromClient[1].IsDeletedFile.Should().BeTrue();
+
+            }
+        }
     }
 }