public void ModelsToString()
            {
                var facts = new Facts()
                {
                    StringFact = "abc"
                };

                Assert.Equal("{\"stringFact\":\"abc\"}", facts.ToString());

                var action = new RuleAction()
                {
                    Type = RuleAction.ActionType.Field, Id = "Field1"
                };

                Assert.Equal("Field Field1", action.ToString());

                var condition = new Condition()
                {
                    Id = "id", Op = Condition.Oper.LessThanOrEqual, Value = new IntValue(1)
                };

                Assert.Equal("id LessThanOrEqual 1", condition.ToString());
            }