public static IEnumerable <object[]> GetTestData()
        {
            var factory       = new TerminalLexerFactory();
            var foo           = factory.Create("foo", StringComparer.OrdinalIgnoreCase);
            var bar           = factory.Create("bar", StringComparer.OrdinalIgnoreCase);
            var charlie       = factory.Create("charlie", StringComparer.OrdinalIgnoreCase);
            var listItemLexer = new AlternationLexer(foo, bar, charlie);

            yield return(new object[] { "foo,bar", "foo, bar", listItemLexer });

            yield return(new object[] { "foo ,bar,", "foo, bar", listItemLexer });

            yield return(new object[] { "foo , ,bar,charlie   ", "foo, bar, charlie", listItemLexer });
        }