System.Tests.StringTests.Compare_Invalid C# (CSharp) Method

        public static void Compare_Invalid()
        {
            // Invalid comparison type
            Assert.Throws<ArgumentException>("comparisonType", () => string.Compare("a", "bb", StringComparison.CurrentCulture - 1));
            Assert.Throws<ArgumentException>("comparisonType", () => string.Compare("a", "bb", StringComparison.OrdinalIgnoreCase + 1));
            Assert.Throws<ArgumentException>("comparisonType", () => string.Compare("a", 0, "bb", 0, 1, StringComparison.CurrentCulture - 1));
            Assert.Throws<ArgumentException>("comparisonType", () => string.Compare("a", 0, "bb", 0, 1, StringComparison.OrdinalIgnoreCase + 1));

            // IndexA < 0
            Assert.Throws<ArgumentOutOfRangeException>("offset1", () => string.Compare("a", -1, "bb", 0, 1));
            Assert.Throws<ArgumentOutOfRangeException>("indexA", () => string.Compare("a", -1, "bb", 0, 1, StringComparison.CurrentCulture));

            // IndexA > stringA.Length
            Assert.Throws<ArgumentOutOfRangeException>("length1", () => string.Compare("a", 2, "bb", 0, 1));
            Assert.Throws<ArgumentOutOfRangeException>("indexA", () => string.Compare("a", 2, "bb", 0, 1, StringComparison.CurrentCulture));

            // IndexB < 0
            Assert.Throws<ArgumentOutOfRangeException>("offset2", () => string.Compare("a", 0, "bb", -1, 1));
            Assert.Throws<ArgumentOutOfRangeException>("indexB", () => string.Compare("a", 0, "bb", -1, 1, StringComparison.CurrentCulture));

            // IndexB > stringB.Length
            Assert.Throws<ArgumentOutOfRangeException>("length2", () => string.Compare("a", 0, "bb", 3, 0));
            Assert.Throws<ArgumentOutOfRangeException>("indexB", () => string.Compare("a", 0, "bb", 3, 0, StringComparison.CurrentCulture));

            // Length < 0
            Assert.Throws<ArgumentOutOfRangeException>("length1", () => string.Compare("a", 0, "bb", 0, -1));
            Assert.Throws<ArgumentOutOfRangeException>("length", () => string.Compare("a", 0, "bb", 0, -1, StringComparison.CurrentCulture));

            // There is a subtle behavior difference between the string.Compare that accepts a StringComparison parameter,
            // and the one that does not. The former includes short-circuiting logic for nulls BEFORE the length/
            // index parameters are validated (but after the StringComparison is), while the latter does not. As a result,
            // this will not throw:
            // string.Compare(null, -1, null, -1, -1, StringComparison.CurrentCulture)
            // but this will:
            // string.Compare(null, -1, null, -1, -1)

            // These tests ensure that the argument validation stays in order.

            // Compare accepting StringComparison
            Assert.Throws<ArgumentException>("comparisonType", () => string.Compare(null, 0, null, 0, 0, StringComparison.CurrentCulture - 1)); // comparisonType should be validated before null short-circuiting...
            // Tests to ensure null is short-circuited before validating the arguments are in the Compare() theory
            Assert.Throws<ArgumentOutOfRangeException>("length", () => string.Compare("foo", -1, "foo", -1, -1, StringComparison.CurrentCulture)); // length should be validated before indexA/indexB
            Assert.Throws<ArgumentOutOfRangeException>("indexA", () => string.Compare("foo", -1, "foo", -1, 3, StringComparison.CurrentCulture)); // then indexA
            Assert.Throws<ArgumentOutOfRangeException>("indexB", () => string.Compare("foo", 0, "foo", -1, 3, StringComparison.CurrentCulture)); // then indexB
            // Then the optimization where we short-circuit if strA == strB && indexA == indexB, or length == 0, is tested in the Compare() theory.

            // Compare not accepting StringComparison
            Assert.Throws<ArgumentOutOfRangeException>("length1", () => string.Compare(null, -1, null, -1, -1));
            Assert.Throws<ArgumentOutOfRangeException>("length2", () => string.Compare(null, 0, "bar", 4, 0));
            Assert.Throws<ArgumentOutOfRangeException>("offset1", () => string.Compare(null, -1, null, -1, 0));
            Assert.Throws<ArgumentOutOfRangeException>("offset2", () => string.Compare(null, 0, null, -1, 0));
            Assert.Throws<ArgumentOutOfRangeException>("string1", () => string.Compare(null, 1, null, 1, 1));
            Assert.Throws<ArgumentOutOfRangeException>("string2", () => string.Compare("bar", 1, null, 1, 1));
        }