Mockito spy方法调用未被检测 明尼苏达大学Coursera作业问题

• 你当前代码中创建的mockRecipe spy实例没有被注入到业务调用链路里：coffeeMaker.makeCoffee执行时用到的是stubRecipies数组里普通的recipe1实例，Mockito无法监控到非spy实例的方法调用，自然验证失败
• 你给mockRecipe加的@InjectMocks注解完全无效，该注解是用于给被测对象注入依赖，不是给spy对象本身加的

直接把你需要监控的Recipe实例做成spy，放到stubRecipies数组的对应位置即可，不需要修改任何业务类代码，调整后的测试代码如下：

@RunWith(MockitoJUnitRunner.class)    
public class CoffeeMakerTest {
    
    //-----------------------------------------------------------------------
    //  数据成员
    //-----------------------------------------------------------------------
    private Recipe recipe1;
    private Recipe recipe2;
    private Recipe recipe3;
    private Recipe recipe4;
    private Recipe recipe5;
    
    private Recipe [] stubRecipies; 
    
    private CoffeeMaker coffeeMaker;

    private RecipeBook recipeBookStub;
    // 删掉无效的@InjectMocks注解，自行控制spy的注入逻辑
    private Recipe spyRecipe;

    @Before
    public void setUp() throws RecipeException {
        
        recipeBookStub = mock(RecipeBook.class);
        coffeeMaker = new CoffeeMaker(recipeBookStub, new Inventory());
        
        // 创建spy对象，配置属性和原测试用的recipe1完全一致
        spyRecipe = Mockito.spy(new Recipe());
        spyRecipe.setName("Coffee");
        spyRecipe.setAmtChocolate("0");
        spyRecipe.setAmtCoffee("3");
        spyRecipe.setAmtMilk("1");
        spyRecipe.setAmtSugar("1");
        spyRecipe.setPrice("50");
        
        //配置recipe2
        recipe2 = new Recipe();
        recipe2.setName("Mocha");
        recipe2.setAmtChocolate("20");
        recipe2.setAmtCoffee("3");
        recipe2.setAmtMilk("1");
        recipe2.setAmtSugar("1");
        recipe2.setPrice("75");
        
        //配置recipe3
        recipe3 = new Recipe();
        recipe3.setName("Latte");
        recipe3.setAmtChocolate("0");
        recipe3.setAmtCoffee("3");
        recipe3.setAmtMilk("3");
        recipe3.setAmtSugar("1");
        recipe3.setPrice("100");
        
        // 把spy放到数组第一个位置，对应测试用的recipeToPurchase=0的场景
        stubRecipies = new Recipe [] {spyRecipe, recipe2, recipe3};
    }

    @Test
    public void testHowManyTimeGetIsCalled() {
        
        when(recipeBookStub.getRecipes())
        .thenReturn(stubRecipies);
        
        coffeeMaker.makeCoffee(0, spyRecipe.getPrice());
        
        // 验证spy实例的方法调用次数即可
        verify(spyRecipe, times(1)).getAmtCoffee();        
    }
}

Mockito的spy只会记录该实例本身的方法调用，必须保证业务逻辑实际调用的是你创建的spy实例，才能正确统计调用次数。本方案不需要修改任何CoffeeMaker、Inventory、Recipe的业务代码，仅调整测试侧的实例构造逻辑即可满足需求。

内容的提问来源于stack exchange，提问作者Edwin