Mockito:想要但未被调用 [英] Mockito: Wanted but not invoked

问题描述

我有以下测试方法:

MyClass myClass= Mockito.mock(MyClass.class);
Mockito.when(myClass.methodUsedInMethodBeingTested(Matchers.any(MyTypeParam.class))).thenReturn(Collections.<X, Y> emptyMap());

assertNull(myClass.methodToTest(myObject));
Mockito.verify(myClass).methodUsedInMethodBeingTested(Matchers.any(MyTypeParam.class));

methodUsedInMethodBeingTested是我要模拟并返回空映射的方法.但是我收到的失败消息是

The methodUsedInMethodBeingTested is a method that I want to mock and return an empty map. But I am getting the failure message saying

想要但未调用myClass.methodUsedInMethodBeingTested()

Wanted but not invoked myClass.methodUsedInMethodBeingTested()

.

MyClass
{
   public XYZ methodToTest()
   {
    ....
    ....
    Map<X,Y> mp = methodUsedInMethodBeingTested(myTypeParam);
    .....
   }

   public Map<X,Y> methodUsedInMethodBeingTested(MyTypeParam myTypeParam)
   {
    .....
   }
}

推荐答案

您误解了什么是模拟.做事的时候

You're misunderstanding what a mock is. When you're doing

MyClass myClass = Mockito.mock(MyClass.class);
// ...
assertNull(myClass.methodToTest(myObject));

您实际上并没有在真实对象上调用methodToTest.您正在模拟上调用methodToTest，默认情况下，该模拟不执行任何操作并返回null，除非已将其存根.引用 Mockito文档:

You're not actually invoking methodToTest on your real object. You're invoking methodToTest on the mock, which by default, does nothing and return null, unless it was stubbed. Quoting from Mockito docs:

默认情况下，对于所有返回值的方法，mock返回null，空集合或适当的原始/原始包装器值(例如:0，false，...用于int/Integer，布尔值/布尔值，...) .

By default, for all methods that return value, mock returns null, an empty collection or appropriate primitive/primitive wrapper value (e.g: 0, false, ... for int/Integer, boolean/Boolean, ...).

这说明了您随后出现的错误:该方法实际上并未在模拟中调用.

This explains your subsequent error: the method was really not invoked on the mock.

您似乎想要的是 spy 代替:

It seems what you want here is a spy instead:

您可以创建真实对象的间谍.当您使用间谍时，将调用 real 方法(除非对某个方法进行了打桩).

You can create spies of real objects. When you use the spy then the real methods are called (unless a method was stubbed).

但请注意警告:由于调用的是真实方法，因此您不应使用Mockito.when，而应使用Mockito.doReturn(...).when，否则该方法将被真正调用一次.如果考虑表达式:

A note of warning though: since it is the real methods that are getting called, you should not use Mockito.when but prefer Mockito.doReturn(...).when, otherwise the method will be called once for real. If you consider the expression:

Mockito.when(myClass.methodUsedInMethodBeingTested(Matchers.any(MyTypeParam.class))).thenReturn(Collections.<X, Y> emptyMap());
             ^-----------------------------------^
                 this will be invoked by Java

必须评估方法when的参数，但这意味着将调用方法methodUsedInMethodBeingTested.由于我们有一个间谍，因此将调用它的真正方法.因此，请改用:

the argument of the method when must be evaluated, but this means the method methodUsedInMethodBeingTested will be invoked. And since we have a spy, it is the real method that will be invoked. So, instead, use:

MyClass spy = Mockito.spy(new MyClass());
Mockito.doReturn(Collections.<X, Y> emptyMap()).when(spy).methodUsedInMethodBeingTested(Matchers.any(MyTypeParam.class));
assertNull(spy.methodToTest(myObject));
Mockito.verify(spy).methodUsedInMethodBeingTested(Matchers.any(MyTypeParam.class));

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