Introduce low level Index/Tree operations

2 files changed, 96 insertions, 0 deletions

diff --git a/LibGit2Sharp.Tests/IndexFixture.cs b/LibGit2Sharp.Tests/IndexFixture.cs
index f6c1690a..1b401bc7 100644
--- a/LibGit2Sharp.Tests/IndexFixture.cs
+++ b/LibGit2Sharp.Tests/IndexFixture.cs
@@ -278,5 +278,67 @@ namespace LibGit2Sharp.Tests
                 Assert.Equal(2, repoRead.Index.Count);
             }
         }
+
+        [Fact]
+        public void CanResetFullyMergedIndexFromTree()
+        {
+            string path = CloneStandardTestRepo();
+
+            const string testFile = "new_tracked_file.txt";
+
+            // It is sufficient to check just one of the stage area changes, such as the added file,
+            // to verify that the index has indeed been read from the tree.
+            using (var repo = new Repository(path))
+            {
+                const string headIndexTreeSha = "e5d221fc5da11a3169bf503d76497c81be3207b6";
+
+                Assert.True(repo.Index.IsFullyMerged);
+                Assert.Equal(FileStatus.Added, repo.Index.RetrieveStatus(testFile));
+
+                var headIndexTree = repo.Lookup<Tree>(headIndexTreeSha);
+                Assert.NotNull(headIndexTree);
+                repo.Index.Reset(headIndexTree);
+
+                Assert.True(repo.Index.IsFullyMerged);
+                Assert.Equal(FileStatus.Untracked, repo.Index.RetrieveStatus(testFile));
+            }
+
+            // Check that the index was persisted to disk.
+            using (var repo = new Repository(path))
+            {
+                Assert.Equal(FileStatus.Untracked, repo.Index.RetrieveStatus(testFile));
+            }
+        }
+
+        [Fact]
+        public void CanResetIndexWithUnmergedEntriesFromTree()
+        {
+            string path = CloneMergedTestRepo();
+
+            const string testFile = "one.txt";
+
+            // It is sufficient to check just one of the stage area changes, such as the modified file,
+            // to verify that the index has indeed been read from the tree.
+            using (var repo = new Repository(path))
+            {
+                const string headIndexTreeSha = "1cb365141a52dfbb24933515820eb3045fbca12b";
+
+                Assert.False(repo.Index.IsFullyMerged);
+                Assert.Equal(FileStatus.Staged, repo.Index.RetrieveStatus(testFile));
+
+                var headIndexTree = repo.Lookup<Tree>(headIndexTreeSha);
+                Assert.NotNull(headIndexTree);
+                repo.Index.Reset(headIndexTree);
+
+                Assert.True(repo.Index.IsFullyMerged);
+                Assert.Equal(FileStatus.Modified, repo.Index.RetrieveStatus(testFile));
+            }
+
+            // Check that the index was persisted to disk.
+            using (var repo = new Repository(path))
+            {
+                Assert.Equal(FileStatus.Modified, repo.Index.RetrieveStatus(testFile));
+            }
+        }
     }
 }
diff --git a/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs b/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
index c6e724c1..622891aa 100644
--- a/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
+++ b/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
@@ -361,6 +361,40 @@ namespace LibGit2Sharp.Tests
         }
 
         [Fact]
+        public void CreatingATreeFromIndexWithUnmergedEntriesThrows()
+        {
+            using (var repo = new Repository(MergedTestRepoWorkingDirPath))
+            {
+                Assert.False(repo.Index.IsFullyMerged);
+
+                Assert.Throws<UnmergedIndexEntriesException>(
+                    () => repo.ObjectDatabase.CreateTree(repo.Index));
+            }
+        }
+
+        [Fact]
+        public void CanCreateATreeFromIndex()
+        {
+            string path = CloneStandardTestRepo();
+
+            using (var repo = new Repository(path))
+            {
+                const string expectedIndexTreeSha = "0fe0fd1943a1b63ecca36fa6bbe9bbe045f791a4";
+
+                // The tree representing the index is not in the db.
+                Assert.Null(repo.Lookup(expectedIndexTreeSha));
+
+                var tree = repo.ObjectDatabase.CreateTree(repo.Index);
+                Assert.NotNull(tree);
+                Assert.Equal(expectedIndexTreeSha, tree.Id.Sha);
+
+                // The tree representing the index is now in the db.
+                tree = repo.Lookup<Tree>(expectedIndexTreeSha);
+                Assert.NotNull(tree);
+            }
+        }
+
+        [Fact]
         public void CanCreateACommit()
         {
             string path = CloneBareTestRepo();