DoesNotStartWith
It returns true if string does not start with the character otherwise returns false if you pass null or empty string, false will be returned.
Source
public static bool DoesNotStartWith(this string input, string pattern)
{
return string.IsNullOrEmpty(pattern) ||
input.IsNullOrEmptyOrWhiteSpace() ||
!input.StartsWith(pattern, StringComparison.CurrentCulture);
}Example
Assert.IsTrue("Test".DoesNotStartWith('?'));