Spock tests fail with NullPointerException once global GroovyMock was used polluting grails testing environment

Question

I noticed sometimes my tests would fail after repeated runs. I realized that it happens once I use a GroovyMock([global:true], SomeClass). The mocked classes no longer work in other Specification classes.

Example where a global mock can be setup:

@TestFor(EmploymentService)
class EmploymentServiceSpec extends Specification {

    Agreement agreement
    Member member

    def setup() {
        agreement = GroovyMock([global: true], Agreement)
        member = GroovyMock([global: true], Member)
    }

    def "some test"() {
    ...
    }

Other class where you need the real thing:

@TestFor(OtherService)
class OtherServiceSpec extends Specification {

    Agreement agreement
    Member member

    def setup() {
        agreement = new Agreement()
        member = new Member()
    }

    def "some test"() {
        member.someMethod() // would throw NPE here
    }

How can I turn off / clean up global mocks once I finished using them in a Specification?

Answer 1

Use @ConfineMetaClassChanges([Your, GloballyMocked, Classes]) on the method or class where you use global mocks to revert the global effect after usage.

More in ConfineMetaClassChanges documentation

Source: One blog covered this, pointing to a GitHub discussion, where they pointed to using @ConfineMetaClassChanges([%%MOCKED_CLASS%%]).