Espresso - how to wait for idle without an assertion/view interaction?

Question

I would like to simply block the instrumentation (test) thread until Espresso is idle.

fun test(){
    // do some stuff
    Espresso.waitForIdle()
    // do some more stuff once Espresso reports that the application is idle
}

What's the best way to do this?

note: Espresso.waitForIdle() is a method I made up

user_3781068 · Answer

There is also Espresso.onIdle(), but the documentation warns Only call this method for tests that do not interact with any UI elements, but require Espresso's main thread synchronisation! https://developer.android.com/reference/android/support/test/espresso/Espresso.html#onIdle()

user_10695663 · Answer

There is also the following:

InstrumentationRegistry.getInstrumentation().waitForIdle {

}

which run the code inside lambda after it is idle.