    @Test
    public void value_comparison_returns_true_when_field_value_matches_expression() throws Exception {

        QueryExpression q = EvalTestContext.queryExpressionFromJson("{'field':'field4','op':'>','rvalue':3.5}");
        QueryEvaluator qe = QueryEvaluator.getInstance(q, md);

        QueryEvaluationContext ctx = qe.evaluate(jsonDoc);

        Assert.assertTrue(ctx.getResult());
    }