add tests for CaseInsensitiveEnumValues param

Author: regme

tests/CommandLine.Tests/Unit/Core/InstanceBuilderTests.cs

@@ -30,6 +30,19 @@ private static ParserResult<T> InvokeBuild<T>(string[] arguments)
                 Enumerable.Empty<ErrorType>());
         }
 
+        private static ParserResult<T> InvokeBuildEnumValuesCaseIgnore<T>(string[] arguments)
+            where T : new()
+        {
+            return InstanceBuilder.Build(
+                Maybe.Just<Func<T>>(() => new T()),
+                (args, optionSpecs) => Tokenizer.ConfigureTokenizer(StringComparer.Ordinal, false, false)(args, optionSpecs),
+                arguments,
+                StringComparer.Ordinal,
+                true,
+                CultureInfo.InvariantCulture,
+                Enumerable.Empty<ErrorType>());
+        }
+
         private static ParserResult<T> InvokeBuildImmutable<T>(string[] arguments)
         {
             return InstanceBuilder.Build(
@@ -261,6 +274,27 @@ public void Parse_enum_value(string[] arguments, Colors expected)
             // Teardown
         }
 
+        [Theory]
+        [InlineData(new[] { "--colors", "red" }, Colors.Red)]
+        [InlineData(new[] { "--colors", "green" }, Colors.Green)]
+        [InlineData(new[] { "--colors", "blue" }, Colors.Blue)]
+        [InlineData(new[] { "--colors", "0" }, Colors.Red)]
+        [InlineData(new[] { "--colors", "1" }, Colors.Green)]
+        [InlineData(new[] { "--colors", "2" }, Colors.Blue)]
+        public void Parse_enum_value_ignore_case(string[] arguments, Colors expected)
+        {
+            // Fixture setup in attribute
+
+            // Exercize system 
+            var result = InvokeBuildEnumValuesCaseIgnore<Simple_Options_With_Enum>(
+                arguments);
+
+            // Verify outcome
+            expected.ShouldBeEquivalentTo(((Parsed<Simple_Options_With_Enum>)result).Value.Colors);
+
+            // Teardown
+        }
+
         [Fact]
         public void Parse_enum_value_with_wrong_index_generates_BadFormatConversionError()
         {