Overriding Expectations Defined in the Test Set-Up

If you define expectations¹ in the set-up of a test in order to put the object under test into a known state, you sometimes want to ignore those expectations during the test itself. For example, you might allow calls to some mock objects during set-up and then want to expect calls to those mock objects during the test. If you just define additional expectations in the test, the allowing expectations defined in the set-up will take precedence² and the test's expectations will never seem to be met, thereby failing the test.

In this situation, use a state machine³ to control when the expectations are valid. This state machine represents the state of the test, rather than the state of the objects with which the object under test communicates.

1. Define a state machine named, for example, "test".
2. In the test set-up, define expectations that are valid when the "test" state machine is not in the "fully-set-up" state.
3. At the end of the test set-up, move the "test" state machine into the "fully-set-up" state.
4. Define expectations in your tests as usual.

The result is that the expectations defined in the set-up to only apply when the test is not "running" will be ignored during the test itself.

public class ChildTest extends MockObjectTestCase {
    States test = states("test");

    Parent parent = mock(Parent.class);

    // This is created in setUp
    Child child;
    
    @Override
    public void setUp() {
        checking(new Expectations() {{
            ignoring (parent).addChild(child); when(test.isNot("fully-set-up"));
        }});
        
        // Creating the child adds it to the parent
        child = new Child(parent);
        
        test.become("fully-set-up");
    }
    
    public void testRemovesItselfFromOldParentWhenAssignedNewParent() {
        Parent newParent = context.mock(Parent.class, "newParent");
        
        checking(new Expectations() {{
            oneOf (parent).removeChild(child);
            oneOf (newParent).addChild(child);
        }});
        
        child.reparent(newParent);
    }
}

@RunWith(JMock.class)
public class ChildTest {
    Mockery context = new JUnit4Mockery();
    States test = mockery.states("test");

    Parent parent = context.mock(Parent.class);

    // This is created in setUp
    Child child;
    
    @Before
    public void createChildOfParent() {
        mockery.checking(new Expectations() {{
            ignoring (parent).addChild(child); when(test.isNot("fully-set-up"));
        }});
        
        // Creating the child adds it to the parent
        child = new Child(parent);
        
        test.become("fully-set-up");
    }
    
    @Test
    public void removesItselfFromOldParentWhenAssignedNewParent() {
        Parent newParent = context.mock(Parent.class, "newParent");
        
        context.checking(new Expectations() {{
            oneOf (parent).removeChild(child);
            oneOf (newParent).addChild(child);
        }});
        
        child.reparent(newParent);
    }
}

public class ChildTest extends TestCase {
    Mockery context = new Mockery();
    States test = context.states("test");

    Parent parent = context.mock(Parent.class);

    // This is created in setUp
    Child child;
    
    @Override
    public void setUp() {
        context.checking(new Expectations() {{
            ignoring (parent).addChild(child); when(test.isNot("fully-set-up"));
        }});
        
        // Creating the child adds it to the parent
        child = new Child(parent);
        
        test.become("fully-set-up");
    }
    
    public void testRemovesItselfFromOldParentWhenAssignedNewParent() {
        Parent newParent = context.mock(Parent.class, "newParent");
        
        context.checking(new Expectations() {{
            oneOf (parent).removeChild(child);
            oneOf (newParent).addChild(child);
        }});
        
        child.reparent(newParent);
    }
}