Mockito在使用@Mock时将Null值注入Spring bean？

问题描述

由于我是Spring Test MVC的新手，我不明白这个问题。我从 http://markchensblog.blogspot.in/search/label/Spring

As I am new to Spring Test MVC I don't understand this problem. I took the code below from http://markchensblog.blogspot.in/search/label/Spring

变量 mockproductService 未从Application Context注入，它包含 null @Mock 注释并获得断言错误时code>值。

Variable mockproductService is not injected from Application Context and it contains null values while using @Mock annotation and getting assetion error.

我目前遇到的断言错误如下：

The Assertion error I currently encounter is as follows:

java.lang.AssertionError: Model attribute 'Products' expected:<[com.pointel.spring.test.Product@e1b42, com.pointel.spring.test.Product@e1f03]> but was:<[]>
    at org.springframework.test.util.AssertionErrors.fail(AssertionErrors.java:60)
    at org.springframework.test.util.AssertionErrors.assertEquals(AssertionErrors.java:89)
    at org.springframework.test.web.servlet.result.ModelResultMatchers$2.match(ModelResultMatchers.java:68)
    at org.springframework.test.web.servlet.MockMvc$1.andExpect(MockMvc.java:141)
    at com.pointel.spring.test.ProductControllerTest.testMethod(ProductControllerTest.java:84)

注意：如果我使用 @Autowired 而不是 @Mock 它工作正常。

Note: If I use @Autowired instead of @Mock it is working fine.

测试控制器类

RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration(locations={"classpath:mvc-dispatcher-servlet.xml"})
@TestExecutionListeners({ DependencyInjectionTestExecutionListener.class})
public class ProductControllerTest {

    @Autowired
    private WebApplicationContext wac;

    private MockMvc mockMvc;

   @InjectMocks
    private ProductController productController;

    @Mock
    //@Autowired
    private ProductService mockproductService;


    @Before
    public void setup() {

    MockitoAnnotations.initMocks(this);

    List<Product> products = new ArrayList<Product>();
    Product product1 = new Product();
    product1.setId(new Long(1));

    Product product2 = new Product();
    product2.setId(new Long(2));

    products.add(product1);
    products.add(product2);

    Mockito.when(mockproductService.findAllProducts()).thenReturn(products);

    this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build();

    }

    @Test
    public void testMethod() throws Exception {

    List<Product> products = new ArrayList<Product>();

    Product product1 = new Product();
    product1.setId(new Long(1));

    Product product2 = new Product();
    product2.setId(new Long(2));

    products.add(product1);
    products.add(product2);

    RequestBuilder requestBuilder = MockMvcRequestBuilders.get("/products");

    this.mockMvc.perform(requestBuilder).
        andExpect(MockMvcResultMatchers.status().isOk())
        .andExpect(MockMvcResultMatchers.model().attribute("Products", products))
           //.andExpect(MockMvcResultMatchers.model().size(2))
        .andExpect(MockMvcResultMatchers.view().name("show_products"));


    }
}

控制器类

@Controller
public class ProductController {

    @Autowired
    private ProductService productService;

    @RequestMapping("/products")
    public String testController(ModelMap model){
        model.addAttribute("Products",productService.findAllProducts());
        return "show_products";
    }
}

WebServletContext mvc-dispatcher-servlet.xml

WebServletContext mvc-dispatcher-servlet.xml

<bean id="someDependencyMock" class="org.mockito.Mockito" factory-method="mock">
    <constructor-arg value="com.pointel.spring.test.ProductService" />
</bean>
    <context:component-scan base-package="com.pointel.spring.test" />

<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" >
    <property name="prefix" value="/WEB-INF/jsp/" />
    <property name="suffix" value=".jsp" />
</bean>

推荐答案

对我来说，目前还不清楚Spring和Mockito的组合当你从引用的博客源中获取它应该按预期工作。至少我可以解释你的观察结果：

For me it's unclear how the combination of Spring and Mockito as you took it from the referenced blog source should work at all as expected. At least I may explain your observation:

• 你的测试（ this.mockMvc.perform（））正在处理Spring创建的Web应用程序上下文。在该上下文中， ProductController 由Spring实例化（ context：component-scan ）。然后将 productService 与您在 mvc-dispatcher-servlet.xml 中创建的Mockito模拟器自动装配为 someDependencyMock 。


• 如果您通过 @Autowired mockproductService / code>， Spring 从其上下文中注入 someDependencyMock 实例。所以你的 Mockito.when（）调用在这个实例上正常工作，该实例已正确连接到 ProductController ，如上所述之前。


• 但如果您通过 @Mock 注入 mockproductService ， Mockito 注入一个新 ProductService 的实例，而不是Spring上下文之一，因为它根本不了解Spring 。所以你的 Mockito.when（）调用不能在Spring自动装配的模拟上运行，因此 someDependencyMock 保持未初始化。

• Your test (this.mockMvc.perform()) is working on the web application context created by Spring. In that context ProductController was instantiated by Spring (context:component-scan). The productService was then autowired with the Mockito mock you created in mvc-dispatcher-servlet.xml as someDependencyMock.
• If you inject the mockproductService via @Autowired, Spring injects the someDependencyMock instance from its context. So your Mockito.when() call works correctly on this instance, which was already correctly wired to the ProductController as mentioned before.
• But if you inject the mockproductService via @Mock, Mockito injects a new instance of ProductService, not the one of the Spring context, since it knows nothing about Spring at all. So your Mockito.when() call does not operate on the mock which was autowired by Spring and thus someDependencyMock stays uninitialized.

所以我不清楚博客的原始代码是如何运作的：

So what's left unclear for me about how the original code from the blog worked at all is:

• 使用 @InjectMocks 注释的 productController 属性将是由Mockito初始化，甚至正确连接到测试类中的 mockproductService 。但Spring对该对象一无所知，也不会在 this.mockMvc.perform（）调用中使用它。所以我假设如果你只用 @Autowired 注入 mockproductService 你的测试按预期工作，即使你删除了 productController 属性和测试类中的 MockitoAnnotations.initMocks（）调用。

• The productController property annotated with @InjectMocks will be initialized by Mockito and even correctly wired to the mockproductService in the test class. But Spring does not know anything about that object and won't use it in this.mockMvc.perform() calls. So I assume if you inject mockproductService only with @Autowired your test works as intended even if you delete both the productController property and the MockitoAnnotations.initMocks() call in your test class.

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