public void FirstSwap()
        {
#if !DEBUG
        Assert.Multiple(() => {
#endif
            var expected = new[] { "ac", "ab" };
            var actual = _object.FirstSwap(new[] { "ab", "ac" });
            Assert.Equal(expected, actual);

            expected = new[] { "ay", "by", "cy", "cx", "bx", "ax", "aaa", "azz" };
            actual = _object.FirstSwap(new[] { "ax", "bx", "cx", "cy", "by", "ay", "aaa", "azz" });
            Assert.Equal(expected, actual);

            expected = new[] { "ay", "by", "ax", "bx", "ai", "aj", "bx", "by" };
            actual = _object.FirstSwap(new[] { "ax", "bx", "ay", "by", "ai", "aj", "bx", "by" });
            Assert.Equal(expected, actual);

            expected = new[] { "ay", "bx", "cy", "ax", "cx", "aaa", "abb" };
            actual = _object.FirstSwap(new[] { "ax", "bx", "cx", "ay", "cy", "aaa", "abb" });
            Assert.Equal(expected, actual);

            expected = new[] { "every", "does", "ice", "easy", "it", "eaten" };
            actual = _object.FirstSwap(new[] { "easy", "does", "it", "every", "ice", "eaten" });
            Assert.Equal(expected, actual);

            expected = new[] { "lily", "over", "water", "swims", "of", "list", "words", "wait" };
            actual = _object.FirstSwap(new[] { "list", "of", "words", "swims", "over", "lily", "water", "wait" });
            Assert.Equal(expected, actual);

            expected = new[] { "42", "8", "16", "15", "23", "4" };
            actual = _object.FirstSwap(new[] { "4", "8", "15", "16", "23", "42" });
            Assert.Equal(expected, actual);

            expected = new[] { "aaa" };
            actual = _object.FirstSwap(new[] { "aaa" });
            Assert.Equal(expected, actual);

            expected = new string[0];
            actual = _object.FirstSwap(new string[0]);
            Assert.Equal(expected, actual);

            expected = new[] { "a", "b", "c", "xx", "yy", "zz" };
            actual = _object.FirstSwap(new[] { "a", "b", "c", "xx", "yy", "zz" });
            Assert.Equal(expected, actual);
#if !DEBUG
});
#endif
        }