Enforce Index low level operations test coverage

Author: nulltoken

LibGit2Sharp.Tests/IndexFixture.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.IO;
 using System.Linq;
 using LibGit2Sharp.Tests.TestHelpers;
@@ -443,5 +444,54 @@ public void AddingAnEntryToTheIndexFromAUnknwonFileInTheWorkdirThrows()
                 Assert.Throws<LibGit2SharpException>(() => repo.Index.Add(filePath));
             }
         }
+
+        [Fact]
+        public void CanMimicGitAddAll()
+        {
+            var path = SandboxStandardTestRepoGitDir();
+            using (var repo = new Repository(path))
+            {
+                var before = repo.RetrieveStatus();
+                Assert.True(before.Any(se => se.State == FileStatus.Untracked));
+                Assert.True(before.Any(se => se.State == FileStatus.Modified));
+                Assert.True(before.Any(se => se.State == FileStatus.Missing));
+
+                StageAllAdditionsRemovalsAndModifications(repo);
+
+                var after = repo.RetrieveStatus();
+                Assert.False(after.Any(se => se.State == FileStatus.Untracked));
+                Assert.False(after.Any(se => se.State == FileStatus.Modified));
+                Assert.False(after.Any(se => se.State == FileStatus.Missing));
+            }
+        }
+
+        private void StageAllAdditionsRemovalsAndModifications(IRepository repo)
+        {
+            var changes = repo.Diff.Compare<TreeChanges>(null, true,
+                compareOptions: new CompareOptions { Similarity = SimilarityOptions.None });
+
+            foreach (TreeEntryChanges treeEntryChanges in changes)
+            {
+                switch (treeEntryChanges.Status)
+                {
+                    case ChangeKind.Unmodified:
+                        continue;
+
+                    case ChangeKind.Added:
+                    case ChangeKind.Modified:
+                        repo.Index.Add(treeEntryChanges.Path);
+                        continue;
+
+                    case ChangeKind.Deleted:
+                        repo.Index.Remove(treeEntryChanges.Path);
+                        continue;
+
+                    default:
+                        throw new InvalidOperationException(
+                            string.Format(CultureInfo.InvariantCulture, "Entry '{0}' bears an unexpected ChangeKind '{1}'",
+                                treeEntryChanges.Path, treeEntryChanges.Status));
+                }
+            }
+        }
     }
 }