在 SpringBoot 应用程序中使用 Mockito

Question

我熟悉SpringBoot，我写了一个小应用程序。它有一个ProductRepository扩展CrudRepository。我ProductService是这样的：

public interface ProductService {
Iterable<Product> listAllProducts();
Product getProductById(Integer id);
Product saveProduct(Product product);
void deleteProduct(Integer id);
}

ProductServiceImpl类自动电线ProductRepository，并提供使用ProductRepository实现。

我的应用程序按预期运行，这就是我测试存储库的方式。

@RunWith(SpringRunner.class)
@SpringBootTest(classes = {RepositoryConfiguration.class})
public class ProductRepositoryTest {
private ProductRepository productRepository;
@Autowired
public void setProductRepository(ProductRepository productRepository) {
this.productRepository = productRepository;
}
@Test
public void testSaveProduct(){
//setup product
Product product = new Product();
product.setDescription("Shirt");
product.setPrice(new BigDecimal("18.95"));
product.setProductId("1234");        
assertNull(product.getId()); //null before save
productRepository.save(product);
assertNotNull(product.getId()); //not null after save
//fetch from DB
Product fetchedProduct = productRepository.findOne(product.getId());
//should not be null
assertNotNull(fetchedProduct);      
}
}

我想知道如何在没有外部依赖的情况下ProductRepository进行单元测试(上面的测试具有外部依赖项，因此不符合单元测试的条件。我相信这更像是一个集成测试)。

另外，我如何对我的ProductService进行单元测试？我试着用Mockito嘲笑ProductRepository和Product，就像这样：

public class ProductServiceImplTest {
private ProductServiceImpl productServiceImpl;
private ProductRepository productRepository;
private Product product;
@Before
public void setupMock() {
MockitoAnnotations.initMocks(this);
productServiceImpl=new ProductServiceImpl();
productRepository = mock(ProductRepository.class);
product = mock(Product.class);
}
@Test
public void testRetrieveById() throws Exception {
when(productRepository.findOne(5)).thenReturn(product);
assertEquals(product, productServiceImpl.getProductById(5));
}
}

但这就是我得到的：

java.lang.NullPointerException
at    
ProductServiceImpl.getProductById(ProductServiceImpl.java:24)
at  ProductServiceImplTest.testRetrieveById(ProductServiceImplTest.java:36)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at  sun.reflect.NativeMethodAccessorImpl.invoke
(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke
(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at  org.junit.runners.model.FrameworkMethod$1.runReflectiveCall
(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run
(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

我是否正确使用了Mockito.mock()？另外，如果我改用Mockito.spy()会有什么区别？任何帮助将不胜感激。

Answer 1

如果要编写单元测试，请删除所有用于集成测试的不必要的注释。

您还需要在@Before方法中启动模拟：

public class ProductServiceImplTest {
@InjectMocks
private ProductServiceImpl productServiceImpl;
@Mock
private ProductRepository productRepository;
@Mock
private Product product;
@Before
public void setupMock() {
MockitoAnnotations.initMocks(this);
}

我认为在您的情况下，使用mock应该就足够了。

您应该使用spy的唯一时间是在您正在测试的类上调用它，在您的情况下是：

productServiceImpl=new ProductServiceImpl();
prodServiceSpy = spy(productServiceImpl);

并模拟一些您不想调用的实现的方法，或者使用测试场景所需的自定义实现调用的方法。