Check fragment visibility after clicking on Tab from TabLayout that only contains icon using Android Espresso

Question

I'm trying to check if my fragment is visible after performing a click on my tab from my tabLayout which has been set up with view pager.

This is my actual activity code, inside my activity onCreate method:

mViewPager = findViewById(R.id.contentFrameLayout);
mViewPager.setAdapter(mSectionPageAdapter);
mViewPager.setPagingEnabled(false);

//Set up the tab layout to display tabs
tabLayout = findViewById(R.id.homeTabs);
tabLayout.setupWithViewPager(mViewPager);

for (int i = 0; i< tabLayout.getTabCount(); i++) {
        TabLayout.Tab mTab = tabLayout.getTabAt(i);
        if (mTab != null) {
            switch (i){
                case 0:
                    mTab.setTag(WFragment.class.toString());
                    mTab.setIcon(R.drawable.home_icon_svg);
                    break;
                case 1:
                    mTab.setTag(MFragment.class.toString());
                    mTab.setIcon(R.drawable.l_svg);
                    break;
                case 2:
                    //etc..
            }
        }
    }

Here is my instrumentation test:

@Test
public void checkIfMFragmentIsVisible() {
    Matcher<View> matcher = allOf(withTagValue(is((Object) MFragment.class.toString())),
            isDescendantOfA(withId(R.id.homeTabs)));
    onView(matcher).perform(click());
    onView(withId(R.id.mFragmentLayout)).check(matches(isCompletelyDisplayed()));
}

I used information from this link which helped me getting started with creating a matcher and performing a click. However, my test is failing with the following error:

android.support.test.espresso.NoMatchingViewException: No views in hierarchy found matching: (with tag value: is "class com.test.solution.fragments.MFragment" and is descendant of a: with id: 2131296345)
If the target view is not part of the view hierarchy, you may need to use Espresso.onData to load it from one of the following AdapterViews:com.google.maps.api.android.lib6.impl.ce{d55b63a G.ED..C.. ......I. 0,0-0,0}

SUCCESSFUL INSTRUMENTATION TEST:

I tried a dummy test by adding the following in my tabs in my activity:

TabLayout.Tab mTab = tabLayout.getTabAt(i);
            if (mTab != null) {
                switch (i){
                    case 0:
                        mTab.setText("case 0");
                        //etc..
                    case 1:
                        mTab.setText("case 1");
                        //etc..
                    case 2:
                        //etc..

And in my Instrumentation Test:

@Test
public void checkIfMFragmentIsVisible() {
    Matcher<View> matcher = allOf(withText("case 1"),
                isDescendantOfA(withId(R.id.homeTabs)));
        onView(matcher).perform(click());
        onView(withId(R.id.mFragmentLayout)).check(matches(isCompletelyDisplayed()));
}

This test was successful, however, I do not want to use a text in my activity, but I want to use a tag or something else.

Answer 1

My test passed by doing the following:

I create an id file under res/values named ids.xml where I created the following:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <item name="tab_h_id" type="id"/>
    <item name="tab_m_id" type="id"/>
</resources>

Then within my actual activity I added the following under my Tablayout:

for (int i = 0; i< tabLayout.getTabCount(); i++) {
        TabLayout.Tab mTab = tabLayout.getTabAt(i);
        if (mTab != null) {
            switch (i){
                case 0:
                    View tabViewH = ((ViewGroup) tabLayout.getChildAt(0)).getChildAt(i);
                    tabViewH.setId(R.id.tab_h_id); //assigning id for tab view for Espresso testing
                    mTab.setIcon(R.drawable.home_icon_svg);
                    break;
                case 1:
                    View tabViewM = ((ViewGroup) tabLayout.getChildAt(0)).getChildAt(i);
                    tabViewM.setId(R.id.tab_m_id); //assigning id for tab view for Espresso testing
                    mTab.setIcon(R.drawable.l_svg);
                    break;
                case 2:
                    //etc..
            }
        }
    }

Then in my Espresso test I'm using withId instead of withTagValue:

@Test
public void checkIfMFragmentIsVisible() {
    Matcher<View> matcher = allOf(withId(R.id.tab_m_id),
            isDescendantOfA(withId(R.id.homeTabs)));
    onView(matcher).perform(click());
    onView(withId(R.id.mFragmentLayout)).check(matches(isCompletelyDisplayed()));
}