Powermock: UnfinishedStubbingException when mocking constructor (whenNew) and placing return result directly.

[valnaumov]

public class Creator
{
    Creator create()
    {
        throw new MyException();
    }
}

```java
public class MyException
extends RuntimeException
{
}

```java
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest(Creator.class)
public class CreatorTest
{
    @Test(expected = MyException.class)
    public void testThenReturn()
    throws Exception
    {
        Creator creator = new Creator();

        PowerMockito.whenNew(MyException.class)
            .withNoArguments().thenReturn(new MyException());

        creator.create();
    }
}

This test fails with UnfinishedStubbingException. But if I first assign returned exception to a variable

MyException toReturn = new MyException();
PowerMockito.whenNew(MyException.class)
            .withNoArguments().thenReturn(toReturn);

it works as expected.

This is not specific to Exception type of course, but this example illustrates the purpose of creating a variable and not saving it for assertion.

This might be another "trade off", but it's not documented anywhere and I'm just curious why this makes such a difference.

org.mockito:mockito-core:1.10.19
org.powermock:powermock-api-mockito:1.6.2
org.powermock:powermock-module-junit4:1.6.2

Thanks.

[thekingn0thing]

It happens, because then you use new MyException() after whenNew(MyException.class) all calls are intercepted and considered as call to mock object.
So it the same as writewhen(someObject.callMethod()).thenReturn(someObject.callMethod())

But with new call there is one nuance. PowerMock can intercept only modified classes and a test class is modified by default even if it not pointed in @PrepareForTest. Why it was done in such way I cannot say, but if I try to change it some test are failed. Maybe when I'l have enough time I'll investigate the issue.

I suggest you use this small workaround.