JUnit的斷言空 - 使用存根和嘲笑

Question

這裏是我的測試方法：

@Test 
public void shouldReturnUser_whenPassedUser() { 
    // given 
    when(userStub.getUsername()).thenReturn(defaultName); 
    when(userStub.getPassword()).thenReturn(defaultPassword); 
    when(userStub.getEmail()).thenReturn(defaultEmail); 

    // when 
    User savedUser = userServiceBean.saveUser(userStub); 

    // then 
    assertNotNull(savedUser); 
    verify(userRepository, times(1)).save(any(User.class)); 
} 

這裏是我的設置：

@Spy 
@InjectMocks 
private UserServiceBean userServiceBean; 

@Mock 
private UserRepository userRepository; 

@Mock 
private Principal principal; 

@Mock 
private PasswordEncoder passwordEncoder; 

@Mock 
private User userStub; 

private String defaultName = "user"; 
private String defaultPassword = "password"; 
private String defaultEmail = "example@example.com"; 

@Before 
public void init() { 
    MockitoAnnotations.initMocks(this); 
} 

這裏是我的userService.saveUser方法：

public User saveUser(User user) { 
    User newUser = new User(user.getUsername(), user.getEmail(), passwordEncoder.encode(user.getPassword())); 
    return userRepository.save(newUser); 
} 

而我的測試結果：

java.lang.AssertionError 
at org.junit.Assert.fail(Assert.java:86) 
at org.junit.Assert.assertTrue(Assert.java:41) 
at org.junit.Assert.assertNotNull(Assert.java:712) 
at org.junit.Assert.assertNotNull(Assert.java:722) 
at com.doublemc.services.UserServiceBeanTest.shouldReturnUser_whenPassedUser(UserServiceBeanTest.java:93) 
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:498) 
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:498) 
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) 

爲什麼我的方法返回null？我正在使用stubUser，並且告訴他究竟返回到哪個getter（正如我在saveUser方法中所做的那樣）並且它仍然返回null？我應該如何改變那個測試的工作？

Answer 1

您忘了定義userRepository模擬的模擬行爲。所以Mockito使用save的默認返回值null。

這樣定義的行爲：

when(userRepository.save(any(User.class))).thenReturn(new User("saved name", "saved email", "saved password"));