mockito - 模拟连续调用的不同响应

Question

我正在测试过滤器方法，该方法将列表作为输入并为列表中的每个项目调用另一个方法(返回 bool 值)，并计算符合条件的项目数。

Mockito.doReturn(valid)
                .doReturn(inValid)
                .doReturn(valid)
                .doReturn(inValid)
                .doReturn(valid)
                .when(mySpy).isEligible(
                any(Item.class),anyString());

这曾经在要测试的方法在 for 循环中调用 isEligible 时起作用

public int filter(List<Item> items){
    int count=0;
    for(i=0;i<items.size;i++){
        if(isEligible(items.get(i)))
           count++;
    return count;
}

现在我把它改为使用java流

public int filter(List<Item> items){
    items.stream().filter(item -> isEligible(item));
    return items.size;
}

现在我的模拟不工作了，正在调用真正的方法

Answer 1

Stubbing consecutive calls (iterator-style stubbing)使用 thenReturn 进行连续 stub

Sometimes we need to stub with different return value/exception for the same method call. Typical use case could be mocking iterators. Original version of Mockito did not have this feature to promote simple mocking. For example, instead of iterators one could use Iterable or simply collections. Those offer natural ways of stubbing (e.g. using real collections). In rare scenarios stubbing consecutive calls could be useful, though:

 when(mock.someMethod("some arg"))
.thenThrow(new RuntimeException())
.thenReturn("foo");

  //First call: throws runtime exception:
  mock.someMethod("some arg");

  //Second call: prints "foo"
   System.out.println(mock.someMethod("some arg"));

  //Any consecutive call: prints "foo" as well (last stubbing wins).
  System.out.println(mock.someMethod("some arg"));

替代的、较短版本的连续 stub :

when(mock.someMethod("some arg"))
.thenReturn("one", "two", "three");

在你的情况下

Mockito.mock(mySpy.isEligible(any(Item.class))).thenReturn(true,false,false,true);