Add repo.Reset() overload to allow replacing of index entries with commit entries

Fix #165

3 files changed, 106 insertions, 2 deletions

diff --git a/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj b/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj
index 7020fd38..3f85a748 100644
--- a/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj
+++ b/LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj
@@ -62,9 +62,10 @@
     <Compile Include="ObjectDatabaseFixture.cs" />
     <Compile Include="DiffTreeToTreeFixture.cs" />
     <Compile Include="RepositoryOptionsFixture.cs" />
-    <Compile Include="ResetFixture.cs" />
+    <Compile Include="ResetHeadFixture.cs" />
     <Compile Include="LazyFixture.cs" />
     <Compile Include="RemoteFixture.cs" />
+    <Compile Include="ResetIndexFixture.cs" />
     <Compile Include="StatusFixture.cs" />
     <Compile Include="TestHelpers\BaseFixture.cs" />
     <Compile Include="BlobFixture.cs" />
diff --git a/LibGit2Sharp.Tests/ResetFixture.cs b/LibGit2Sharp.Tests/ResetHeadFixture.cs
index b2912701..44d43f06 100644
--- a/LibGit2Sharp.Tests/ResetFixture.cs
+++ b/LibGit2Sharp.Tests/ResetHeadFixture.cs
@@ -6,7 +6,7 @@ using Xunit.Extensions;
 
 namespace LibGit2Sharp.Tests
 {
-    public class ResetFixture : BaseFixture
+    public class ResetHeadFixture : BaseFixture
     {
         [Theory]
         [InlineData(true)]
diff --git a/LibGit2Sharp.Tests/ResetIndexFixture.cs b/LibGit2Sharp.Tests/ResetIndexFixture.cs
new file mode 100644
index 00000000..ac9f6815
--- /dev/null
+++ b/LibGit2Sharp.Tests/ResetIndexFixture.cs
@@ -0,0 +1,103 @@
+using System.IO;
+using System.Linq;
+using LibGit2Sharp.Tests.TestHelpers;
+using Xunit;
+using Xunit.Extensions;
+
+namespace LibGit2Sharp.Tests
+{
+    public class ResetIndexFixture : BaseFixture
+    {
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void ResetANewlyInitializedRepositoryThrows(bool isBare)
+        {
+            SelfCleaningDirectory scd = BuildSelfCleaningDirectory();
+
+            using (Repository repo = Repository.Init(scd.DirectoryPath, isBare))
+            {
+                Assert.Throws<LibGit2SharpException>(() => repo.Reset());
+            }
+        }
+
+        [Fact]
+        public void ResettingInABareRepositoryThrows()
+        {
+            using (var repo = new Repository(BareTestRepoPath))
+            {
+                Assert.Throws<LibGit2SharpException>(() => repo.Reset());
+            }
+        }
+
+        private bool IsStaged(StatusEntry entry)
+        {
+            if ((entry.State & FileStatus.Added) == FileStatus.Added)
+            {
+                return true;
+            }
+
+            if ((entry.State & FileStatus.Staged) == FileStatus.Staged)
+            {
+                return true;
+            }
+
+            if ((entry.State & FileStatus.Removed) == FileStatus.Removed)
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        [Fact]
+        public void ResetTheIndexWithTheHeadUnstagesEverything()
+        {
+            TemporaryCloneOfTestRepo path = BuildTemporaryCloneOfTestRepo(StandardTestRepoWorkingDirPath);
+
+            using (var repo = new Repository(path.DirectoryPath))
+            {
+                RepositoryStatus oldStatus = repo.Index.RetrieveStatus();
+                Assert.Equal(3, oldStatus.Where(IsStaged).Count());
+
+                repo.Reset();
+
+                RepositoryStatus newStatus = repo.Index.RetrieveStatus();
+                Assert.Equal(0, newStatus.Where(IsStaged).Count());
+            }
+        }
+
+        [Fact]
+        public void CanResetTheIndexToTheContentOfACommit()
+        {
+            TemporaryCloneOfTestRepo path = BuildTemporaryCloneOfTestRepo(StandardTestRepoWorkingDirPath);
+
+            using (var repo = new Repository(path.DirectoryPath))
+            {
+                repo.Reset("be3563a");
+
+                RepositoryStatus newStatus = repo.Index.RetrieveStatus();
+
+                var expected = new[] { "1.txt", "1" + Path.DirectorySeparatorChar + "branch_file.txt", "deleted_staged_file.txt", 
+                    "deleted_unstaged_file.txt", "modified_staged_file.txt", "modified_unstaged_file.txt" };
+
+                Assert.Equal(expected.Length, newStatus.Where(IsStaged).Count());
+                Assert.Equal(expected, newStatus.Removed);
+            }
+        }
+
+        [Fact]
+        public void CanResetTheIndexToASubsetOfTheContentOfACommit()
+        {
+            TemporaryCloneOfTestRepo path = BuildTemporaryCloneOfTestRepo(StandardTestRepoWorkingDirPath);
+
+            using (var repo = new Repository(path.DirectoryPath))
+            {
+                repo.Reset("5b5b025", new[]{ "new.txt" });
+
+                Assert.Equal("a8233120f6ad708f843d861ce2b7228ec4e3dec6", repo.Index["README"].Id.Sha);
+                Assert.Equal("fa49b077972391ad58037050f2a75f74e3671e92", repo.Index["new.txt"].Id.Sha);
+            }
+        }
+    }
+}