public void empty_string_returns_empty_array()
        {
            var cat = new CommaCat("");

            cat.Kittens.Should().BeEquivalentTo(new string[0]);
        }
        public void spaces_are_trimmed()
        {
            var cat = new CommaCat("123 ,45, 6   ,7");

            cat.Kittens.Should().BeEquivalentTo(new[] { "123", "45", "6", "7" });
        }
        public void Null_converts_to_empty_array()
        {
            var cat1 = new CommaCat((string)null);

            cat1.Kittens.Should().BeEquivalentTo(new string[0]);
        }