如何防止服务的metaClass被重写

Question

我试图在集成测试中模拟对外部服务的调用，该服务在grails webflow中使用。该服务不在流或会话作用域中，而是通过依赖注入添加的，请参阅here。

我已经设法想出了一种方法，通过使用ExpandoMetaClass替换服务的metaClass来覆盖服务。这些更改仅在测试单独运行时生效，如果在此测试之前运行了使用相同服务的另一个测试，则metaClass更改将消失。

覆盖metaClass的部分：

static {
    ExpandoMetaClass someService = new ExpandoMetaClass(Object, false)
    someService.invokeMethod = { String name, args ->
        def result = 'success'
        if(name.equals('accessAnotherSystem')
        {
            StackTraceUtils.sanitize(new Throwable()).stackTrace.each
            {
                if(it.methodName.equals('test_method_I_Want_failure_in')
                {
                    result = 'exception'
                }
            }
            return result
        }

        def validMethod = SomeService.metaClass.getMetaMethod(name, args)
        if (validMethod != null)
        {
            validMethod.invoke(delegate, args)
        }
        else
        {
            SomeService.metaClass.invokeMissingMethod(delegate, name, args)
        }
    }
    someService.initialize()
    SomeService.metaClass = someService
}

相关问题：How to change a class's metaClass per test

有没有办法将我的更改保存到测试中，或者是否有其他方法覆盖该服务。

Answer 1

如果您想要在每个测试方法的测试用例中覆盖服务，有一种更简单的方法。看一个例子：

class SomeControllerSpec extends Specification {

    def someService

    void "test any external method for success response"() {
        given: "Mocked service method"
        someService.metaClass.accessAnotherSystem = { arg1, arg2 ->
            return "some success response"
        }

        when: "Any controller method is called which calls this service method"
        // Your action which calls that service method

        then: "Result will processed coming from mocked method"
        // Your code
    }
}

您可以对任何服务测试方法执行相同的操作。如果您想模拟您正在为其编写测试用例的同一服务的方法，那么请执行以下操作。

class SomeServiceSpec extends Specification {

    def someService

    void "test external method call"() {
        given: "Mocked service method"
        someService.metaClass.methodA = { arg1, arg2 ->
            return "some success response"
        }

        when: "A method is called which invokes the another method"
        // Your another service method which call the same method
        someService.methodB()    // Where methodB() invokes the methodA() internally in your code

        then: "Result will processed coming from mocked method"
        // Your code
    }
}