diff: Enhance tree-to-tree diff test coverage

These tests are related to issue libgit2/libgit2sharp#196

tests-clar/diff/tree.c

@@ -25,6 +25,7 @@ void test_diff_tree__cleanup(void)
 	git_tree_free(b);
 
 	cl_git_sandbox_cleanup();
+
 }
 
 void test_diff_tree__0(void)
@@ -320,3 +321,111 @@ void test_diff_tree__checks_options_version(void)
 	cl_git_fail(git_diff_tree_to_tree(&diff, g_repo, a, b, &opts));
 	err = giterr_last();
 }
+
+void process_tree_to_tree_diffing(
+	const char *old_commit,
+	const char *new_commit)
+{
+	g_repo = cl_git_sandbox_init("unsymlinked.git");
+
+	cl_assert((a = resolve_commit_oid_to_tree(g_repo, old_commit)) != NULL);
+	cl_assert((b = resolve_commit_oid_to_tree(g_repo, new_commit)) != NULL);
+
+	cl_git_pass(git_diff_tree_to_tree(&diff, g_repo, a, b, &opts));
+
+	cl_git_pass(git_diff_foreach(
+		diff, diff_file_cb, NULL, NULL, &exp));
+}
+
+void test_diff_tree__symlink_blob_mode_changed_to_regular_file(void)
+{
+	/*
+	* $ git diff  7fccd7..806999
+	* diff --git a/include/Nu/Nu.h b/include/Nu/Nu.h
+	* deleted file mode 120000
+	* index 19bf568..0000000
+	* --- a/include/Nu/Nu.h
+	* +++ /dev/null
+	* @@ -1 +0,0 @@
+	* -../../objc/Nu.h
+	* \ No newline at end of file
+	* diff --git a/include/Nu/Nu.h b/include/Nu/Nu.h
+	* new file mode 100644
+	* index 0000000..f9e6561
+	* --- /dev/null
+	* +++ b/include/Nu/Nu.h
+	* @@ -0,0 +1 @@
+	* +awesome content
+	* diff --git a/objc/Nu.h b/objc/Nu.h
+	* deleted file mode 100644
+	* index f9e6561..0000000
+	* --- a/objc/Nu.h
+	* +++ /dev/null
+	* @@ -1 +0,0 @@
+	* -awesome content
+	*/
+
+	process_tree_to_tree_diffing("7fccd7", "806999");
+
+	cl_assert_equal_i(3, exp.files);
+	cl_assert_equal_i(2, exp.file_status[GIT_DELTA_DELETED]);
+	cl_assert_equal_i(0, exp.file_status[GIT_DELTA_MODIFIED]);
+	cl_assert_equal_i(1, exp.file_status[GIT_DELTA_ADDED]);
+	cl_assert_equal_i(0, exp.file_status[GIT_DELTA_TYPECHANGE]);
+}
+
+void test_diff_tree__symlink_blob_mode_changed_to_regular_file_as_typechange(void)
+{
+	/*
+	 * $ git diff  7fccd7..a8595c
+	 * diff --git a/include/Nu/Nu.h b/include/Nu/Nu.h
+	 * deleted file mode 120000
+	 * index 19bf568..0000000
+	 * --- a/include/Nu/Nu.h
+	 * +++ /dev/null
+	 * @@ -1 +0,0 @@
+	 * -../../objc/Nu.h
+	 * \ No newline at end of file
+	 * diff --git a/include/Nu/Nu.h b/include/Nu/Nu.h
+	 * new file mode 100755
+	 * index 0000000..f9e6561
+	 * --- /dev/null
+	 * +++ b/include/Nu/Nu.h
+	 * @@ -0,0 +1 @@
+	 * +awesome content
+	 * diff --git a/objc/Nu.h b/objc/Nu.h
+	 * deleted file mode 100644
+	 * index f9e6561..0000000
+	 * --- a/objc/Nu.h
+	 * +++ /dev/null
+	 * @@ -1 +0,0 @@
+	 * -awesome content
+	*/
+
+	opts.flags = GIT_DIFF_INCLUDE_TYPECHANGE;
+	process_tree_to_tree_diffing("7fccd7", "a8595c");
+
+	cl_assert_equal_i(2, exp.files);
+	cl_assert_equal_i(1, exp.file_status[GIT_DELTA_DELETED]);
+	cl_assert_equal_i(0, exp.file_status[GIT_DELTA_MODIFIED]);
+	cl_assert_equal_i(0, exp.file_status[GIT_DELTA_ADDED]);
+	cl_assert_equal_i(1, exp.file_status[GIT_DELTA_TYPECHANGE]);
+}
+
+void test_diff_tree__regular_blob_mode_changed_to_executable_file(void)
+{
+	/*
+	 * $ git diff 806999..a8595c
+	 * diff --git a/include/Nu/Nu.h b/include/Nu/Nu.h
+	 * old mode 100644
+	 * new mode 100755
+	 */
+
+	process_tree_to_tree_diffing("806999", "a8595c");
+
+	cl_assert_equal_i(1, exp.files);
+	cl_assert_equal_i(0, exp.file_status[GIT_DELTA_DELETED]);
+	cl_assert_equal_i(1, exp.file_status[GIT_DELTA_MODIFIED]);
+	cl_assert_equal_i(0, exp.file_status[GIT_DELTA_ADDED]);
+	cl_assert_equal_i(0, exp.file_status[GIT_DELTA_TYPECHANGE]);
+}