在开发模式下运行Play应用时出现Mockito问题

Question

I am writing unit tests for a Play 1.x app, and using Mockito to easily create mock instances on the fly. I am running in development mode, so that I don't have to restart the app frequently.

The problem comes when I change the code, and the re-run my unit tests without restarting the Play app. I get the following exception:

A java.lang.ClassCastException has been caught, Cannot cast services.MyService$$EnhancerByMockitoWithCGLIB$$12cee5a2 to services.MyService

When I restart te app, and re-run the tests, all of them execute fine, but it takes me up to a couple of minutes to restart every time. Is there something that could be done?

Answer 1

This is a known problem when working with Play, the lib classloader stays the same while the developed code is being changed on each reload, which causes issues for libraries that cache reflection related things, there a CCE .

You have to disable the class cache by overriding the default configuration, see the complete documentation .

The idea is that in your test code base, create a class with the following qualified name org.mockito.configuration.MockitoConfiguration that will extends org.mockito.configuration.DefaultMockitoConfiguration and override the method boolean enableClassClache() to return false.