Class.metaclass.static say can not get static on null

Question

Was writing unit test cases and at one point I needed to do some meta programming to test a method as below.

 void "test method:resolver"(){
        setup:"mocked resolver"
        ContextHolder.getMetaClass().static.getBean = {
            Resolver resolver = Mock(Resolver)
            resolver(_) >> {HttpServletRequest request1->
                return 1;
            }
        }

        and:"mocked getAppName"
        CoreUtil.metaClass.static.getAppName = {
            return "$apiName"
        }

        when:
        UserGroupRole userGroupRole = service.resolve(username)

        then:
        userGroupRole != null

        where:
         apiName            || username
        "core-blog"      || "test11"
    }

Following are the scenarios that I have gone through for running test cases:

• When running test case individually, It works perfectly.
• When running test case as a whole Specification i.e. run the Specification class itself, It works perfectly
• But when running the test cases as whole by

grails test-app :unit

It fails saying Class.metaclass.static say can not get static on null

Please help!

Answer 1

If you're making metaclass changes in your tests, you need to clean up those metaclass changes in a cleanup step at the end of each test. Otherwise you risk test pollution.

setup
    metaclass work
when 
then 
cleanup:
    revoke the metaclass changes here
where