Add test for revert+rename bug.

tests/resources/revert-rename.git/HEAD

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+ref: refs/heads/master

tests/resources/revert-rename.git/config

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+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+	logallrefupdates = true

tests/resources/revert-rename.git/objects/info/packs

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+P pack-4363774fb90141e8aa7a326ace0566366114e869.pack
+

tests/resources/revert-rename.git/packed-refs

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+# pack-refs with: peeled fully-peeled sorted 
+ecef6a85173b6f446873a13f7b5a7b54a85cd912 refs/heads/master

tests/resources/revert-rename.git/refs/heads/master

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+ecef6a85173b6f446873a13f7b5a7b54a85cd912

tests/revert/rename.c

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+#include "clar.h"
+#include "clar_libgit2.h"
+
+#include "git2/revert.h"
+#include "../merge/merge_helpers.h"
+
+#define TEST_REPO_PATH "revert-rename.git"
+
+static git_repository *repo;
+
+/* Fixture setup and teardown */
+void test_revert_rename__initialize(void)
+{
+	repo = cl_git_sandbox_init(TEST_REPO_PATH);
+}
+
+void test_revert_rename__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+/* Attempt a revert when there is a file rename AND change of file mode,
+ * but the file contents remain the same. Check that the file mode doesn't
+ * change following the revert.
+ */
+void test_revert_rename__automerge(void)
+{
+  git_commit *head_commit, *revert_commit;
+  git_oid revert_oid;
+  git_index *index;
+  git_reference *head_ref;
+
+  struct merge_index_entry merge_index_entries[] = {
+    { 0100644, "f0f64c618e1646d2948a456ed7c4bcfad5536d68", 0, "goodmode" }};
+
+  cl_git_pass(git_repository_head(&head_ref, repo));
+  cl_git_pass(git_reference_peel((git_object **)&head_commit, head_ref, GIT_OBJECT_COMMIT));
+
+  cl_git_pass(git_oid_fromstr(&revert_oid, "7b4d7c3789b3581973c04087cb774c3c3576de2f"));
+  cl_git_pass(git_commit_lookup(&revert_commit, repo, &revert_oid));
+
+  cl_git_pass(git_revert_commit(&index, repo, revert_commit, head_commit, 0, NULL));
+  cl_assert(merge_test_index(index, merge_index_entries, 1));
+
+  git_commit_free(revert_commit);
+  git_commit_free(head_commit);
+  git_index_free(index);
+  git_reference_free(head_ref);
+}