public void Given_EmptyString_Expect_ThrowsIllegalArgumentException(string s, int[] e)
{
Assert.Throws <ArgumentException>(() => Substring.FindLongestSubstring(s));
}
public void Given_StringWithCharacters_Expect_ArrayWithDataAboutSubstring(string s, int[] e)
{
int[] a = Substring.FindLongestSubstring(s);
Assert.True(Enumerable.SequenceEqual(a, e), "actual: [" + a[0] + ", " + a[1] + ", " + a[2] + ", " + a[3] + "]");
}
