includes a mixin in a child class.
Inheritance: MixinCommandBase
        public void ClassWithNativeFields_CanExecuteMixinCommand_CannotExecute()
        {
            WithSourceFiles(Files.Person);
            var person = CreateClass(nameof(PersonWithNativeTypes));
            var fieldDeclarations = person.SourceCode.DescendantNodes().OfType<FieldDeclarationSyntax>();

            var mixinFactory = new MixinReferenceFactory(Semantic);

            foreach (var fieldDeclaration in fieldDeclarations)
            {
                var mixin = mixinFactory.Create(fieldDeclaration);
                var mixinCommand = new IncludeMixinCommand(mixin);
                Assert.IsFalse(mixinCommand.CanExecute(person));
            }
        }