ComponentTest.java

// Register your Idling Resource before any tests regarding this component
@Before
 public void registerIdlingResource() {
    IdlingRegistry.getInstance().register(EspressoIdlingResource.getIdlingResource());
}

// Unregister your Idling Resource so it can be garbage collected and does not leak any memory
@After
public void unregisterIdlingResource() {
    IdlingRegistry.getInstance().unregister(EspressoIdlingResource.getIdlingResource());
}