Mockito：類的所有實例的模擬實例方法

Question

我正在嘗試存根特定類的實例方法，以便當此Foo類的任何實例調用此實例方法doSomething ，將返回相同的object （請參閱下面的代碼）。 但是，mockito 不允許驗證或存根之外的任何匹配器。

Bar object = new Bar();
given(any(Foo.class).doSomething(Arg.class)).willReturn(object);

在Foo.class ：

Bar doSomething(Arg param) {
    Bar bar = new Bar();
    // Do something with bar
    return bar;
}

我可以通過 Mockito 實現這個目標嗎？ 謝謝！

Answer 1

如果您希望Foo在對Foo任何實例調用doSomething方法時返回相同的Bar實例，則應使用PowerMock 。 下面是一個例子：

@RunWith(PowerMockRunner.class)
@PrepareForTest(Foo.class)
public class FooMockAllInstanceTest {

    @Test
    public void testMockInstanceofObjectCreation() throws Exception {
        Bar mockBar = PowerMockito.mock(Bar.class);
        when(mockBar.sayHello()).thenReturn("Hi John!");
        PowerMockito.whenNew(Bar.class)
                .withNoArguments()
                .thenReturn(mockBar);

        Foo myFooOne = new Foo();
        assertEquals(mockBar,  myFooOne.doSomething("Jane"));

        Foo myFooTwo = new Foo();
        assertEquals(mockBar,  myFooTwo.doSomething("Sarah"));

        Baz bazOne = new Baz();
        assertEquals(mockBar, bazOne.doSomething("Sam"));

        Baz bazTwo = new Baz();
        assertEquals(mockBar, bazTwo.doSomething("Nina"));
    }
}

即使調用Baz此示例也將返回相同的Bar對象。 這是Baz課，

public class Baz {

    public Bar doSomething(String name) {
        Foo foo = new Foo();
        return foo.doSomething(name);
    }
}

更新 2

還有另一種稍微好一點的方法來使用 PowerMock 進行測試。 來了，

@Test
public void testStubbingMethod() throws Exception {
    Bar mockBar = PowerMockito.mock(Bar.class);
    when(mockBar.sayHello()).thenReturn("Hi John!");

    PowerMockito.stub(PowerMockito.method(Foo.class, "doSomething",
            String.class)).toReturn(mockBar);

    Foo myFooOne = new Foo();
    assertEquals(mockBar, myFooOne.doSomething("Jane"));

    Foo myFooTwo = new Foo();
    assertEquals(mockBar, myFooTwo.doSomething("Sarah"));

    Baz bazOne = new Baz();
    assertEquals(mockBar, bazOne.doSomething("Sam"));

    Baz bazTwo = new Baz();
    assertEquals(mockBar, bazTwo.doSomething("Nina"));
}