Mocking in InstrumentationTestCase

Question

I try to mock a method in my instrumentation test but it fails and I am looking for a solution to solve it.

public class MyTest extends InstrumentationTestCase {

    private Context mAppCtx;

    @Override
    public void setUp() throws Exception {
        super.setUp();

        Context context = mock(Context.class);

        mAppCtx = getInstrumentation().getContext().getApplicationContext();                

        when(mAppCtx.createPackageContext(PACKAGE_NAME, 0)).thenReturn(context);

    }

A crash happens on the following line:

when(mAppCtx.createPackageContext(PACKAGE_NAME, 0)).thenReturn(context);

And I got following error:

org.mockito.exceptions.misusing.MissingMethodInvocationException:
when() requires an argument which has to be 'a method call on a mock'.
For example:
when(mock.getArticles()).thenReturn(articles);

Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods *cannot* be stubbed/verified.
2. inside when() you don't call method on mock but on some other object.
3. the parent of the mocked class is not public.
It is a limitation of the mock engine.

Answer 1

You need to mock each method invocation of: getInstrumentation().getContext().getApplicationContext();

Example:

Instrumentation inst = mock(Instrumentation.class);
Context instContext = mock(Context.class);
ApplicationContext mAppCtx= mock(ApplicationContext.class);
when(getInstrumentation()).thenReturn(inst);
when(inst.getContext()).thenReturn(instContext);
when(instContext.getApplicationContext()).thenReturn(mAppCtx);
when(mAppCtx.createPackageContext(PACKAGE_NAME, 0)).thenReturn(context);