Introduce ObjectDatabase.ShortenObjectId()

Fix #677

1 files changed, 42 insertions, 0 deletions

diff --git a/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs b/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
index 649cb26e..091876d8 100644
--- a/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
+++ b/LibGit2Sharp.Tests/ObjectDatabaseFixture.cs
@@ -556,5 +556,47 @@ namespace LibGit2Sharp.Tests
                     () => repo.ObjectDatabase.CalculateHistoryDivergence(null, repo.Head.Tip));
             }
         }
+
+        [Fact]
+        public void CanShortenObjectIdentifier()
+        {
+            /*
+             * $ echo "aabqhq" | git hash-object -t blob --stdin
+             * dea509d0b3cb8ee0650f6ca210bc83f4678851ba
+             * 
+             * $ echo "aaazvc" | git hash-object -t blob --stdin
+             * dea509d097ce692e167dfc6a48a7a280cc5e877e
+             */
+
+            string path = CloneBareTestRepo();
+            using (var repo = new Repository(path))
+            {
+                repo.Config.Set("core.abbrev", 4);
+
+                Blob blob1 = CreateBlob(repo, "aabqhq\n");
+                Assert.Equal("dea509d0b3cb8ee0650f6ca210bc83f4678851ba", blob1.Sha);
+
+                Assert.Equal("dea5", repo.ObjectDatabase.ShortenObjectId(blob1));
+                Assert.Equal("dea509d0b3cb", repo.ObjectDatabase.ShortenObjectId(blob1, 12));
+                Assert.Equal("dea509d0b3cb8ee0650f6ca210bc83f4678851b", repo.ObjectDatabase.ShortenObjectId(blob1, 39));
+
+                Blob blob2 = CreateBlob(repo, "aaazvc\n");
+                Assert.Equal("dea509d09", repo.ObjectDatabase.ShortenObjectId(blob2));
+                Assert.Equal("dea509d09", repo.ObjectDatabase.ShortenObjectId(blob2, 4));
+                Assert.Equal("dea509d0b", repo.ObjectDatabase.ShortenObjectId(blob1));
+                Assert.Equal("dea509d0b", repo.ObjectDatabase.ShortenObjectId(blob1, 7));
+
+                Assert.Equal("dea509d0b3cb", repo.ObjectDatabase.ShortenObjectId(blob1, 12));
+                Assert.Equal("dea509d097ce", repo.ObjectDatabase.ShortenObjectId(blob2, 12));
+            }
+        }
+
+        private static Blob CreateBlob(Repository repo, string content)
+        {
+            using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(content)))
+            {
+                return repo.ObjectDatabase.CreateBlob(stream);
+            }
+        }
     }
 }