public static void IndexOfAny(string s, char[] anyOf, int startIndex, int count, int expected) { if (startIndex + count == s.Length) { if (startIndex == 0) { Assert.Equal(expected, s.IndexOfAny(anyOf)); } Assert.Equal(expected, s.IndexOfAny(anyOf, startIndex)); } Assert.Equal(expected, s.IndexOfAny(anyOf, startIndex, count)); }