英文:
Mockito: When any instance invokes method, thenReturn something
问题
以下是您要翻译的内容：
我对Mockito非常陌生，有一个类似这样的类：
public class A {
private B b;
public B getB() { return b; }
// ...
}
和
public class B {
private C c;
public C getC() { return c; }
// ...
}
我正在使用Mockito为类A编写单元测试，并尝试实现以下行为，其中B是一个模拟对象：
when(a.getB().getC()).thenReturn(mock(C.class))
when(any(mock(C.class)).doSomething()).thenReturn("somethingElse") // 这不起作用。
如何在任何模拟的C类实例调用doSomething()时返回"somethingElse"？我不想将此行为绑定到任何一个特定的mock(C.class)实例。
请注意，我已经将HTML编码（例如"）还原为正常的引号。如果您需要进一步的帮助，请告诉我。
英文:
I'm very new to Mockito and have a class like
public class A {
private B b;
public B getB() { return b; }
// ...
}
and
public class B {
private C c;
public C getC() { return c; }
// ...
}
I am writing unit tests using Mockito for class A, and trying to achieve the following behavior, where B is a mock:
when(a.getB().getC()).thenReturn(mock(C.class))
when(any(mock(C.class)).doSomething()).thenReturn("somethingElse") // This doesn't work.
How can I return "somethingElse" when any mocked instance of C calls doSomething()? I don't want to bind this behavior to any one particular mock(C.class) instance.
答案1
得分: 1
以下是翻译好的部分：
首先，您必须将测试对象视为一个单元，并模拟其他一切。所以，因为您正在测试类A，您不能模拟A的方法。
这是如何使用Mockito使用注解来模拟B实例的方法：
@MockitoSettings
public class ATest {
@Mock
private B b;
@InjectMocks
private A a;
@Test
void testExample() {
C c = mock(C.class);
when(b.getC()).thenReturn(c);
when(c.doSomething()).thenReturn("somethingElse");
// a.getB() == b
}
}
那么这里发生了什么呢？
注解@Mock正在初始化一个类型为B的模拟对象，并将字段变量b设置为它。
@InjectMocks正在收集所有@Mock字段，并设置对象中的字段。这是您的测试对象。
现在，您的A实例有一个模拟的B对象。而在B内部，还有一个C。由于B是一个模拟对象，方法getC()实际上什么都不做。您必须为它设置一些功能。在测试中，我初始化了一个本地的模拟C实例，以便从getC()返回。
因此，现在当A对象访问模拟的B并获取C时，它将获得这个本地变量c以供使用。因此，您可以为这个对象设置模拟函数。
英文:
First of all, you have to treat your test subject as a unit, and mock everything else. So since you're testing class A you cannot mock As methods.
Here's how you would use Mockito to mock the instance of B using annotations:
@MockitoSettings
public class ATest {
@Mock
private B b;
@InjectMocks
private A a;
@Test
void testExample() {
C c = mock(C.class):
when(b.getC()).thenReturn(c);
when(c.doSomething()).thenReturn("somethingElse");
// a.getB() == b
}
}
So what is happening here?
The annotation @Mock is intializing a mocked object of type B and setting the field variable b to it.
@InjectMocks is collecting all @Mock fields and setting the fields in the object. This is your test subject.
Now your A instance has a mocked B object. And within B you have C. Since B is a mocked object the method getC() doesn't do anthing at all. You have to stub it with some functionality. In the test, I've initialized a local mocked C instance to be returned from getC().
So now when A object accesses the mocked B and get C it will get this local variable c to use. So you can stub this object with mocked functions.
答案2
得分: 0
不要添加mock()，它用于创建新的模拟对象。
像这样：
when(any(C.class).doSomething()).thenReturn("somethingElse");
英文:
Do not add the ```mock()`` its used for creating new mocks.
Like this
when(any(C.class).doSomething()).thenReturn("somethingElse");
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