An extension of RobolectricTestRunner that overrides a binding in the test module. The runner specializes a TestLifecycle which prepares the injector with the new module.

gistfile1.txt

package com.pivotallabs.post_followers.test_util;

import com.google.inject.AbstractModule;
import com.google.inject.Injector;
import com.google.inject.util.Modules;
import com.pivotallabs.post_followers.api.PostFollowersService;
import com.pivotallabs.post_followers.injection.PostFollowersModule;
import com.pivotallabs.post_followers.injection.PostFollowersTestModule;
import org.junit.runners.model.InitializationError;
import org.robolectric.DefaultTestLifecycle;
import org.robolectric.Robolectric;
import org.robolectric.RobolectricTestRunner;
import org.robolectric.TestLifecycle;
import roboguice.RoboGuice;

import static org.mockito.Mockito.mock;

public class MockApiServiceTestRunner extends RobolectricTestRunner {
    public MockApiServiceTestRunner(Class<?> testClass) throws InitializationError {
        super(testClass);
    }

    @Override
    protected Class<? extends TestLifecycle> getTestLifecycleClass() {
        return MockApiServerTestLifecycle.class;
    }

    public static class MockApiServerTestLifecycle extends DefaultTestLifecycle {
        @Override
        public void prepareTest(Object test) {
            Injector injector = RoboGuice.setBaseApplicationInjector(
                    Robolectric.application,
                    RoboGuice.DEFAULT_STAGE,
                    RoboGuice.newDefaultRoboModule(Robolectric.application),
                    Modules.override(new PostFollowersModule())
                            .with(new PostFollowersTestModule(), new MockApiServerTestModule()));
            injector.injectMembers(test);
        }
    }

    public static class MockApiServerTestModule extends AbstractModule {
        @Override
        protected void configure() {
            bind(PostFollowersService.class).toInstance(mock(PostFollowersService.class));
        }
    }
}