private void TestRegExpToSql(PatternParser outputDefn, string input, string expected)
        {
            var patternOpts = RegexParser.Parse(input);

            Assert.AreEqual(expected, outputDefn.Render(patternOpts));
        }
        private void TestSqlPattern(PatternParser inputDefn, PatternParser outputDefn, string input, string expected)
        {
            var patternOpts = inputDefn.Parse(input);

            Assert.AreEqual(expected, outputDefn.Render(patternOpts));
        }