How to select a specific Tab position in Tab Layout using Espresso testing

Issue

I have a tab layout with view pager .I am using Espresso for testing my android app. In my previous projects I use the tab title to perform click for selecting a tab Position like follows.

    Espresso.onView(ViewMatchers.withText("MAP"))
            .perform(ViewActions.click());

Right now I a have 114 tabs. So I can't use above method for randomly select these tabs for testing. Is there any way I can select tabs by its position. I already check other solutions but none of those helped me.

Solution

Should be doable with a custom ViewAction. Something like this:

fun selectTabAtPosition(tabIndex: Int): ViewAction {
    return object : ViewAction {
        override fun getDescription() = "with tab at index $tabIndex"

        override fun getConstraints() = allOf(isDisplayed(), isAssignableFrom(TabLayout::class.java))

        override fun perform(uiController: UiController, view: View) {
            val tabLayout = view as TabLayout
            val tabAtIndex: TabLayout.Tab = tabLayout.getTabAt(tabIndex)
                    ?: throw PerformException.Builder()
                            .withCause(Throwable("No tab at index $tabIndex"))
                            .build()

            tabAtIndex.select()
        }
    }
}

and the usage:

onView(withId(R.id.tab_layout)).perform(selectTabAtPosition(99))

Answered By - Be_Negative