Espresso test outputs in timeout

I am doing usual test such as :

runTestOnUiThread(new Runnable() {
            @Override
            public void run() {
                some_button.performClick();
               onView(withId(R.id.some_other_button)).check(matches(isDisplayed()));

            }
        });
}

But the test never ends. Now if I take onView method and if I put it after the runTestOnUiThread statement, then the result is the same. Someone has an idea ?