public void CoalesceTest()
 {
     LinqToSparqlExpTranslator<Track> target = new LinqToSparqlExpTranslator<Track>();
     target.TypeTranslator = new XsdtTypeConverter();
     string testVal = "hello";
     string defaultVal = "world";
     Expression e = Expression.Coalesce(Expression.Constant(testVal), Expression.Constant(defaultVal));
     target.StringBuilder = new StringBuilder();
     target.Coalesce(e);
 }