Espresso - how to get current activity to test Fragments?

Question

I have been playing around with Espresso tests for couple weeks now and I finally decided to start testing Fragments.

Immediately I ran into a problem,

Answer 1

Here is lelloman's solution with a slight change in Kotlin:

import android.app.Activity
import androidx.test.platform.app.InstrumentationRegistry.getInstrumentation
import androidx.test.runner.lifecycle.ActivityLifecycleMonitorRegistry
import androidx.test.runner.lifecycle.Stage

object EspressoHelper {
    fun getCurrentActivity(): Activity? {
        var currentActivity: Activity? = null
        getInstrumentation().runOnMainSync { run { currentActivity = ActivityLifecycleMonitorRegistry.getInstance().getActivitiesInStage(Stage.RESUMED).elementAtOrNull(0) } }
        return currentActivity
    }
}