Outline for an Espresso test that interacts with BottomSheets in a reliable way

SampleBottomSheetTest.kt

@Test
fun clickButtonInsideExpandedBottomSheet() {
  val sheetBehavior = activity.getBottomSheetBehavior()
  val expandedSheetIdlingResource = BottomSheetStateResource(sheetBehavior, STATE_EXPANDED)
  val settledSheetIdlingResource = BottomSheetSettledResource(sheetBehavior)
 
  // Wait for settled state
  withBottomSheetResource(settledSheetIdlingResource) {
    // Use BottomSheetSetStateAction to expand the Bottom Sheet
  }
 
  // Wait for expanded state
  withBottomSheetResource(expandedSheetIdlingResource) {
    // Click on button inside Bottom Sheet content
  }
 
  // Assert that button had the intended effect
}
 
private fun withBottomSheetResource(
  sheetIdlingResource: IdlingResource,
  actionsAndAssertions: () -> Unit
) {
  with(sheetIdlingResource) {
    idlingRegistry.register(this)
    try {
      actionsAndAssertions.invoke()
    } finally {
      idlingRegistry.unregister(this)
    }
  }
}

Thanks for getting back to me even after so many year since your post! Thanks for the help :)

hey, we added following dummy assertion to force bottom sheet idling resource to wait until it is done.

 Espresso.onIdle { }
 actionsAndAssertions.invoke()

this ensure that espresso waits for bottom sheet resource to become idle