How to run tests on an activities fragment

Question

I am just starting out wih `junit` and the first issue I'm running into is, how should I test fragments? The activity being tested has 1 fragment which is the main layout. ``` @Override protected void setUp() throws Exception { super.setUp(); Intent intent = new Intent(getInstrumentation().getTargetContext(), ActivityWelcome.class); startActivity(intent, null, null); FragmentManager fragmentManager = getActivity().getSupportFragmentManager(); mFragmentWelcome = (FragmentWelcome) fragmentManager.findFragmentByTag(FragmentWelcome.TAG); if (mFragmentWelcome == null) { mFragmentWelcome= FragmentWelcome.newInstance(); fragmentManager .beginTransaction() .replace(android.R.id.content, mFragmentWelcome, FragmentWelcome.TAG) .commit(); } } ``` I then go on to test the layout: ``` @SmallTest public void testLayout() { ImageButton buttonImage = (ImageButton) getActivity().findViewById(my.package.R.id.button_invites); assertNotNull(buttonImage); assertEquals("ImageButton Invite has an invalid dr…

Accepted Answer

Actually you have to wait for the UI thread composes the main view with the fragments.

I had the same errors and so I looked at the sources of Robotium to see how they handle that. The response is they use some methods that wait the required time.

For fragment you can use something like that before performing your assertions :

```
protected Fragment waitForFragment(String tag, int timeout) {
        long endTime = SystemClock.uptimeMillis() + timeout;
        while (SystemClock.uptimeMillis() <= endTime) {

Fragment fragment = getActivity().getSupportFragmentManager().findFragmentByTag(tag);
            if (fragment != null) {
                return fragment;
            }
        }
        return null;
    }
```

I use a timeout of 5000ms, it seems to work well.

So in your code you should replace

```
mFragmentWelcome = (FragmentWelcome) fragmentManager.findFragmentByTag(FragmentWelcome.TAG);
```

by

```
mFragmentWelcome = (FragmentWelcome) waitForFragment(FragmentWelcome.TAG, 5000);
```

EDIT : This response assumes your junit extends `ActivityInstrumentationTestCase2<T>`

How to run tests on an activities fragment

Solution

Problem