What is "IdlingResourceTimeoutException" in Espresso?
<p>I recently using espresso to do test with my android app. But sometimes the test case passed, sometimes not. It is a very long async task takes about 30 second to finish it. When it failed, it throws me this exception:</p>

<p>IdlingResourceTimeoutException</p>

<p>So does anyone know why this happens and what is the meaning of this exception?</p>