ActivityInstrumentationTestCase2 and use of static finals: fields become null after first test

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 success开发者_Go百科fully! 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?

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

Put a watch point on STATIC_ARRAY and see who modifies it, although there are not too many candidates (since the field is private, there is pretty much only one candidate, the class you just posted, so something is missing from the picture.