public void LowerCaseA_UpToLowerCaseA_ReturnsLowerCaseA()
            {
                var expected = new[] {'a'};

                char[] actual = 'a'.UpTo('a');

                Assert.Equal(expected, actual);
            }
            public void UpperCaseA_UpToUpperCaseA_ReturnsUpperCaseA()
            {
                var expected = new[] {'A'};

                char[] actual = 'A'.UpTo('A');

                Assert.Equal(expected, actual);
            }