public void diff_commonPrefixTest() {
diff_match_patchTest dmp = new diff_match_patchTest();
// Detect any common suffix.
// Null case.
Assert.AreEqual(0, dmp.diff_commonPrefix("abc", "xyz"));
// Non-null case.
Assert.AreEqual(4, dmp.diff_commonPrefix("1234abcdef", "1234xyz"));
// Whole case.
Assert.AreEqual(4, dmp.diff_commonPrefix("1234", "1234xyz"));
}