Testing ViewPager with multiple fragments using android espresso

Question

I am trying to test my app which uses ViewPager. Each page contains fragments but these fragments are not always visible. I want to check visibility of a fragment in the currently visible page.

onView(withId(R.id.container_weather))
    .check(matches(withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE)));

But the problem is that espresso looks are all the pages not just the current page and I get the following error:

android.support.test.espresso.AmbiguousViewMatcherException: 'with id: eu.airpatrol.android:id/container_weather' matches multiple views in the hierarchy...

Answer 1

I had the same problem, however using the condition isCompletelyDisplayed() solved this problem as it only takes into account the on-screen views.

So, something like this should work:

onView(allOf(withId(R.id.container_weather), isCompletelyDisplayed()))
.check(matches(withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE)));

Note: isDisplayed() works too in some cases but it also takes views off-screen into account and won't work if the ViewPager has any other page pr fragment loaded with the same view id.

Answer 2

Your tests are failing because of multiple elements with the same id. You can combine conditions using allOf(...). Then use isDisplayed() to check that matched view is visible on the screen. Below example can work:

onView(allOf(
    withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE),
    withId(R.id.container_weather)))
    .check(matches(isDisplayed()));

Answer 3

Ran into this exact same problem. I was fortunate because the view hierarchies in my ViewPager can be easily identified by their siblings, so I was able to solve this using the hasSibling matcher, like so:

onView(
    allOf(
        hasSibling(withId(R.id.some_sibling)),
        withId(R.id.field_to_test)
    )
).perform(replaceText("123"));

Not a perfect solution as it can be slightly brittle, but in my case I think it was an acceptable compromise.