Add tree to tree Diff feature

2 files changed, 334 insertions, 0 deletions

diff --git a/LibGit2Sharp.Tests/DiffFixture.cs b/LibGit2Sharp.Tests/DiffFixture.cs
new file mode 100644
index 00000000..156346b3
--- /dev/null
+++ b/LibGit2Sharp.Tests/DiffFixture.cs
@@ -0,0 +1,333 @@
+using System.Linq;
+using System.Text;
+using LibGit2Sharp.Tests.TestHelpers;
+using Xunit;
+
+namespace LibGit2Sharp.Tests
+{
+    public class DiffFixture : BaseFixture
+    {
+        //TODO Test binary files (do we have hunks/line callbacks)
+        //TODO What does content contain when dealing with a Binary file?
+        //TODO When does it make sense to expose the Binary property?
+        //TODO The PrintCallBack lacks some context (GitDiffDelta)
+
+        [Fact]
+        public void ComparingATreeAgainstItselfReturnsNoDifference()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Tree tree = repo.Head.Tip.Tree;
+
+                TreeChanges changes = repo.Diff.Compare(tree, tree);
+
+                Assert.Empty(changes);
+            }
+        }
+
+        [Fact]
+        public void RetrievingANonExistentFileChangeReturnsNull()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Tree tree = repo.Head.Tip.Tree;
+
+                TreeChanges changes = repo.Diff.Compare(tree, tree);
+
+                Assert.Null(changes["batman"]);
+            }
+        }
+
+        /*
+         * $ git diff --stat HEAD^..HEAD
+         *  1.txt |    1 +
+         *  1 file changed, 1 insertion(+)
+         */
+        [Fact]
+        public void CanCompareACommitTreeAgainstItsParent()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Tree commitTree = repo.Head.Tip.Tree;
+                Tree parentCommitTree = repo.Head.Tip.Parents.Single().Tree;
+
+                TreeChanges changes = repo.Diff.Compare(parentCommitTree, commitTree);
+
+                Assert.Equal(1, changes.Count());
+                Assert.Equal(1, changes.Added.Count());
+
+                TreeEntryChanges treeEntryChanges = changes["1.txt"];
+
+                Assert.Equal("1.txt", treeEntryChanges.Path);
+                Assert.Equal(ChangeKind.Added, treeEntryChanges.Status);
+                // Also in Added collection
+                Assert.Equal(treeEntryChanges, changes.Added.Single());
+                Assert.Equal(1, treeEntryChanges.LinesAdded);
+
+                Assert.Equal(Mode.Nonexistent, treeEntryChanges.OldMode);
+            }
+        }
+
+        /*
+         * $ git diff --stat origin/test..HEAD
+         *  1.txt                      |    1 +
+         *  1/branch_file.txt          |    1 +
+         *  README                     |    1 +
+         *  branch_file.txt            |    1 +
+         *  deleted_staged_file.txt    |    1 +
+         *  deleted_unstaged_file.txt  |    1 +
+         *  modified_staged_file.txt   |    1 +
+         *  modified_unstaged_file.txt |    1 +
+         *  new.txt                    |    1 +
+         *  readme.txt                 |    2 --
+         *  10 files changed, 9 insertions(+), 2 deletions(-)
+         */
+        [Fact]
+        public void CanCompareACommitTreeAgainstATreeWithNoCommonAncestor()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Tree commitTree = repo.Head.Tip.Tree;
+                Tree commitTreeWithDifferentAncestor = repo.Branches["refs/remotes/origin/test"].Tip.Tree;
+
+                TreeChanges changes = repo.Diff.Compare(commitTreeWithDifferentAncestor, commitTree);
+
+                Assert.Equal(10, changes.Count());
+                Assert.Equal(9, changes.Added.Count());
+                Assert.Equal(1, changes.Deleted.Count());
+
+                Assert.Equal("readme.txt", changes.Deleted.Single().Path);
+                Assert.Equal(new[] { "1.txt", "1/branch_file.txt", "README", "branch_file.txt", "deleted_staged_file.txt", "deleted_unstaged_file.txt", "modified_staged_file.txt", "modified_unstaged_file.txt", "new.txt" },
+                             changes.Added.Select(x => x.Path));
+
+                Assert.Equal(9, changes.LinesAdded);
+                Assert.Equal(2, changes.LinesDeleted);
+                Assert.Equal(2, changes["readme.txt"].LinesDeleted);
+            }
+        }
+
+        /*
+         * $ git diff -M f8d44d7..4be51d6
+         * diff --git a/my-name-does-not-feel-right.txt b/super-file.txt
+         * similarity index 82%
+         * rename from my-name-does-not-feel-right.txt
+         * rename to super-file.txt
+         * index e8953ab..16bdf1d 100644
+         * --- a/my-name-does-not-feel-right.txt
+         * +++ b/super-file.txt
+         * @@ -2,3 +2,4 @@ That's a terrible name!
+         *  I don't like it.
+         *  People look down at me and laugh. :-(
+         *  Really!!!!
+         * +Yeah! Better!
+         *
+         * $ git diff -M --shortstat f8d44d7..4be51d6
+         *  1 file changed, 1 insertion(+)
+         */
+        [Fact(Skip = "Not implemented in libgit2 yet.")]
+        public void CanDetectTheRenamingOfAModifiedFile()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Tree rootCommitTree = repo.Lookup<Commit>("f8d44d7").Tree;
+                Tree commitTreeWithRenamedFile = repo.Lookup<Commit>("4be51d6").Tree;
+
+                TreeChanges changes = repo.Diff.Compare(rootCommitTree, commitTreeWithRenamedFile);
+
+                Assert.Equal(1, changes.Count());
+                Assert.Equal("super-file.txt", changes["super-file.txt"].Path);
+                Assert.Equal("my-name-does-not-feel-right.txt", changes["super-file.txt"].OldPath);
+                //Assert.Equal(1, changes.FilesRenamed.Count());
+            }
+        }
+
+        /*
+         * $ git diff f8d44d7..ec9e401
+         * diff --git a/numbers.txt b/numbers.txt
+         * index 7909961..4625a36 100644
+         * --- a/numbers.txt
+         * +++ b/numbers.txt
+         * @@ -8,8 +8,9 @@
+         *  8
+         *  9
+         *  10
+         * -12
+         * +11
+         *  12
+         *  13
+         *  14
+         *  15
+         * +16
+         * \ No newline at end of file
+         *
+         * $ git diff --shortstat f8d44d7..ec9e401
+         *  1 file changed, 2 insertions(+), 1 deletion(-)
+         */
+        [Fact]
+        public void CanCompareTwoVersionsOfAFileWithATrailingNewlineDeletion()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Tree rootCommitTree = repo.Lookup<Commit>("f8d44d7").Tree;
+                Tree commitTreeWithUpdatedFile = repo.Lookup<Commit>("ec9e401").Tree;
+
+                TreeChanges changes = repo.Diff.Compare(rootCommitTree, commitTreeWithUpdatedFile);
+
+                Assert.Equal(1, changes.Count());
+                Assert.Equal(1, changes.Modified.Count());
+
+                TreeEntryChanges treeEntryChanges = changes.Modified.Single();
+
+                Assert.Equal(2, treeEntryChanges.LinesAdded);
+                Assert.Equal(1, treeEntryChanges.LinesDeleted);
+            }
+        }
+
+        /*
+         * $ git diff --inter-hunk-context=2 f8d44d7..7252fe2
+         * diff --git a/my-name-does-not-feel-right.txt b/my-name-does-not-feel-right.txt
+         * deleted file mode 100644
+         * index e8953ab..0000000
+         * --- a/my-name-does-not-feel-right.txt
+         * +++ /dev/null
+         * @@ -1,4 +0,0 @@
+         * -That's a terrible name!
+         * -I don't like it.
+         * -People look down at me and laugh. :-(
+         * -Really!!!!
+         * diff --git a/numbers.txt b/numbers.txt
+         * index 7909961..4e935b7 100644
+         * --- a/numbers.txt
+         * +++ b/numbers.txt
+         * @@ -1,4 +1,5 @@
+         *  1
+         * +2
+         *  3
+         *  4
+         *  5
+         * @@ -8,8 +9,9 @@
+         *  8
+         *  9
+         *  10
+         * -12
+         * +11
+         *  12
+         *  13
+         *  14
+         *  15
+         * +16
+         * diff --git a/super-file.txt b/super-file.txt
+         * new file mode 100644
+         * index 0000000..16bdf1d
+         * --- /dev/null
+         * +++ b/super-file.txt
+         * @@ -0,0 +1,5 @@
+         * +That's a terrible name!
+         * +I don't like it.
+         * +People look down at me and laugh. :-(
+         * +Really!!!!
+         * +Yeah! Better!
+         *
+         * $ git diff --stat f8d44d7..7252fe2
+         *  my-name-does-not-feel-right.txt |    4 ----
+         *  numbers.txt                     |    4 +++-
+         *  super-file.txt                  |    5 +++++
+         *  3 files changed, 8 insertions(+), 5 deletions(-)
+         */
+        [Fact]
+        public void CanCompareTwoVersionsOfAFileWithADiffOfTwoHunks()
+        {
+            using (var repo = new Repository(StandardTestRepoPath))
+            {
+                Tree rootCommitTree = repo.Lookup<Commit>("f8d44d7").Tree;
+                Tree mergedCommitTree = repo.Lookup<Commit>("7252fe2").Tree;
+
+                TreeChanges changes = repo.Diff.Compare(rootCommitTree, mergedCommitTree);
+
+                Assert.Equal(3, changes.Count());
+                Assert.Equal(1, changes.Modified.Count());
+                Assert.Equal(1, changes.Deleted.Count());
+                Assert.Equal(1, changes.Added.Count());
+
+                TreeEntryChanges treeEntryChanges = changes["numbers.txt"];
+
+                Assert.Equal(3, treeEntryChanges.LinesAdded);
+                Assert.Equal(1, treeEntryChanges.LinesDeleted);
+
+                Assert.Equal(Mode.Nonexistent, changes["my-name-does-not-feel-right.txt"].Mode);
+
+                var expected = new StringBuilder()
+                    .Append("diff --git a/numbers.txt b/numbers.txt\n")
+                    .Append("index 7909961..4e935b7 100644\n")
+                    .Append("--- a/numbers.txt\n")
+                    .Append("+++ b/numbers.txt\n")
+                    .Append("@@ -1,4 +1,5 @@\n")
+                    .Append(" 1\n")
+                    .Append("+2\n")
+                    .Append(" 3\n")
+                    .Append(" 4\n")
+                    .Append(" 5\n")
+                    .Append("@@ -8,8 +9,9 @@\n")
+                    .Append(" 8\n")
+                    .Append(" 9\n")
+                    .Append(" 10\n")
+                    .Append("-12\n")
+                    .Append("+11\n")
+                    .Append(" 12\n")
+                    .Append(" 13\n")
+                    .Append(" 14\n")
+                    .Append(" 15\n")
+                    .Append("+16\n");
+
+                Assert.Equal(expected.ToString(), treeEntryChanges.Patch);
+
+                expected = new StringBuilder()
+                    .Append("diff --git a/my-name-does-not-feel-right.txt b/my-name-does-not-feel-right.txt\n")
+                    .Append("deleted file mode 100644\n")
+                    .Append("index e8953ab..0000000\n")
+                    .Append("--- a/my-name-does-not-feel-right.txt\n")
+                    .Append("+++ /dev/null\n")
+                    .Append("@@ -1,4 +0,0 @@\n")
+                    .Append("-That's a terrible name!\n")
+                    .Append("-I don't like it.\n")
+                    .Append("-People look down at me and laugh. :-(\n")
+                    .Append("-Really!!!!\n")
+                    .Append("diff --git a/numbers.txt b/numbers.txt\n")
+                    .Append("index 7909961..4e935b7 100644\n")
+                    .Append("--- a/numbers.txt\n")
+                    .Append("+++ b/numbers.txt\n")
+                    .Append("@@ -1,4 +1,5 @@\n")
+                    .Append(" 1\n")
+                    .Append("+2\n")
+                    .Append(" 3\n")
+                    .Append(" 4\n")
+                    .Append(" 5\n")
+                    .Append("@@ -8,8 +9,9 @@\n")
+                    .Append(" 8\n")
+                    .Append(" 9\n")
+                    .Append(" 10\n")
+                    .Append("-12\n")
+                    .Append("+11\n")
+                    .Append(" 12\n")
+                    .Append(" 13\n")
+                    .Append(" 14\n")
+                    .Append(" 15\n")
+                    .Append("+16\n")
+                    .Append("diff --git a/super-file.txt b/super-file.txt\n")
+                    .Append("new file mode 100644\n")
+                    .Append("index 0000000..16bdf1d\n")
+                    .Append("--- /dev/null\n")
+                    .Append("+++ b/super-file.txt\n")
+                    .Append("@@ -0,0 +1,5 @@\n")
+                    .Append("+That's a terrible name!\n")
+                    .Append("+I don't like it.\n")
+                    .Append("+People look down at me and laugh. :-(\n")
+                    .Append("+Really!!!!\n")
+                    .Append("+Yeah! Better!\n");
+
+                // TODO: uncomment the line below when https://github.com/libgit2/libgit2/pull/643 is merged into development branch.
+                //Assert.Equal(expected.ToString(), changes.Patch);
+            }
+        }
+    }
+}
diff --git a/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj b/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj
index 9071e3b3..ae793e6a 100644
--- a/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj
+++ b/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj
@@ -47,6 +47,7 @@
   <ItemGroup>
     <Compile Include="ConfigurationFixture.cs" />
     <Compile Include="ObjectDatabaseFixture.cs" />
+    <Compile Include="DiffFixture.cs" />
     <Compile Include="ResetFixture.cs" />
     <Compile Include="LazyFixture.cs" />
     <Compile Include="RemoteFixture.cs" />