Question

This is really looks like some magic is going on and I’m interested to understand why that happens 🙂

Here’s the unit-test I have:

public class SelectThemeActivityTest 
    extends ActivityInstrumentationTestCase2<SelectThemeActivity> {

    private final static int[] STATIC_ARRAY = { 0, 1, 2 };

    public SelectThemeActivityTest() {
        super("com.the7art.simplewallpaper", SelectThemeActivity.class);
    }

    @Override
    protected void setUp() throws Exception {
        super.setUp();
        // some array usage here - will throw NullPointerEcxeption on second test
        // see description below
        STATIC_ARRAY[0] = 2;
    }

    @Override
    protected void tearDown() throws Exception {
        super.tearDown();
    }

    public void testFirst() {

    }
    public void testSecond() {

    }
    public void testThird() {

    }
}

If I run this test case the first test completes successfully and all the rest fail by throwing NullPointerException from setUp() – the line which tries to access STATIC_ARRAY.

What puzzles me even more is the fact that if I change the test case to extend AndroidTestCase instead of ActivityInstrumentationTestCase2, then all tests complete successfully! Magic! 🙂

Also if I remove ‘static’ keyword from STATIC_ARRAY, tests succeed too.

So it’s clear that something is modifying my STATIC_ARRAY by making it null between a test runs, most probably in tearDown() and that something has to do with ActivityInstrumentationTestCase2, but how to track that something? 🙂 Any ideas?

Answer 1

The reason is scrubClass() method called from super.tearDown(): google-groups discussion. A solution is – overriding this method.