Android: Writing test cases for Fragments

Issue

In my previous projects I've done most of the work through Activities and used ActivityInstrumentationTestCase2 as per the document:
http://developer.android.com/tools/testing/activity_testing.html
I have an idea how to work with Activity Test cases; but when it comes to Fragment ,I don't have much idea nor found much documents related to that. So how to write test cases when I have several fragments with one or two actvities? Any example code or sample would be more helpful.

Solution

AndroidX provides a library, FragmentScenario, to create fragments and change their state.

app/build.gradle

dependencies {
    def fragment_version = "1.0.0"
    // ...
    debugImplementation 'androidx.fragment:fragment-testing:$fragment_version'
}

example

@RunWith(AndroidJUnit4::class)
class MyTestSuite {
    @Test fun testEventFragment() {
        // The "fragmentArgs" and "factory" arguments are optional.
        val fragmentArgs = Bundle().apply {
            putInt("selectedListItem", 0)
        }
        val factory = MyFragmentFactory()
        val scenario = launchFragmentInContainer<MyFragment>(
                fragmentArgs, factory)
        onView(withId(R.id.text)).check(matches(withText("Hello World!")))
    }
}

More at official docs.

Answered By - Levon Petrosyan