Ensure spring-boot can use Mockito public API

Problem

Mockito framework integrators need robust public APIs from us. This way, they ship great Mockito integrations to their customers. We want to avoid the situation where framework integrators have to use Mockito internal APIs. This leads to overhead, relying on stale versions of Mockito, class conflicts in runtime.

spring-boot currently uses some internal API from Mockito. See https://github.com/spring-projects/spring-boot/issues/10352 for the problem statement, solution options and chosen design.

Solution

As discussed in spring-boot ticket, here’s the API we would like to prototype:

• New “VerificationStartedListener”
• The instance of listener can be passed on mock creation
• Listener is notified when ‘Mockito.verify’ is invoked but before the verification is triggered
• It is possible to replace the mock object that is being verified (key feature needed by spring-boot)

Example usage

mock(Foo.class, withSettings().verificationStartedListeners(new VerificationStartedListener() {
  public void onVerifyStarted(VerificationStartedEvent event) {
    event.getMock();
    event.setMock(arbitrayObject);
  }
}

[mockitoguy]

Fantastic! I will polish the code / documentation and get the release out soon. Thank you for testing this out and suppling sample project!

[wilkinsona]

@szczepiq This looks great. I’ve built the mockito-spring-boot branch and prototyped the updates required for Spring Boot to use it: https://github.com/wilkinsona/spring-boot/tree/gh-10352. All our tests pass and, as you can hopefully see, Boot’s code is now significantly simpler. Thanks very much.