Java JUnit AssertionError：期望代码引发可丢弃的错误

我正在尝试为抛出自定义异常的方法编写测试。它因断言错误而失败。如何正确捕获异常并通过测试

服务方式：

@Service
public class CustomServiceImpl implements CustomService {
    @Autowired
    UserUtil userUtil;
    public ResultDTO getResultDto (String type, Long id) throws CustomException {
        User user = userUtil.getCurrentUser();
        if (user == null) {
            throw new CustomException("User does not exist");
        }
    }
}

试验方法：

@MockBean
CustomServiceImpl  customServiceImpl ;

@Test
public void test01_getResultDto() {
    UserUtil userUtil = Mockito.mock(UserUtil.class);
    Mockito.when(userUtil.getCurrentUser()).thenReturn(null);
    Assertions.assertThatThrownBy(() -> customServiceImpl.getResultDto (Mockito.anyString(), Mockito.anyLong())) 
        .isInstanceOf(CustomException .class)
        .hasMessage("User does not exist");
}

此测试失败，出现以下错误：

java.lang.AssertionError: Expecting code to raise a throwable.
    at com.ps.service.CustomServiceImplTest.test01_getResultDto(CustomServiceImplTest.java:62)
    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.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
    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.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

---------------------------编辑------------------------ 将代码测试更改为包括以下内容

@Mock
UserUtil userUtil;
@InjectMocks
CustomServiceImpl cutomServiceImpl;

@Before
public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
}

@Test
public void test01_getResultDto() {
    when(userUtil.getCurrentUser()).thenReturn(null);
    assertThatThrownBy(() -> customServiceImpl.getResultDto ("type", 1L)) 
        .isInstanceOf(CustomException .class)
        .hasMessage("User does not exist");
}

看起来很有效

---

感谢评论中的建议。

另一种方法是：

@MockBean
CustomServiceImpl  customServiceImpl ;
@Rule
public ExpectedException exceptionRule = ExpectedException.none();

@Test
public void test01_getResultDto() {
    exceptionRule.expect(CustomException.class);
    UserUtil userUtil = Mockito.mock(UserUtil.class);
    Mockito.when(userUtil.getCurrentUser()).thenReturn(null);
    customServiceImpl.getResultDto ("type", 1L);
}

---

我已经对我的原始代码进行了适当的更改，下面的设置运行良好

@Mock
UserUtil userUtil;
@InjectMocks
CustomServiceImpl cutomServiceImpl;

@Before
public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
}

@Test
public void test01_getResultDto() {
    when(userUtil.getCurrentUser()).thenReturn(null);
    assertThatThrownBy(() -> customServiceImpl.getResultDto ("type", 1L)) 
        .isInstanceOf(CustomException .class)
        .hasMessage("User does not exist");
}

---

您的方法调用customServiceImpl.GetResultTo（）不会引发异常。这就是AssertionError告诉您的。您正在测试一个mock（@MockBean CustomServiceImpl）。那没有道理。在测试服务a时，您应该模拟的是a的依赖关系，即a中使用和注入的服务。您不应该需要Spring集成测试来测试这一点。只有一个简单的旧单元测试。首先使用构造函数注入，而不是字段注入。创建UserUtil（依赖项）的模拟。您可以使用

新建CustomServiceImpl（mockUserUtil）

创建CustomServiceImpl的真实实例。然后你调用你的方法。顺便说一句，这个方法不应该接受任何参数，因为它不使用它们。@JBNizet是正确的。您需要创建CustomServiceImpl的新实例，并将其依赖项（UserUtil）作为模拟注入。另外，您不使用

@MockBean

进行单元测试，而是使用

@Mock

。MockBean用于集成测试。@JBNizet我应该在CustomServiceImpl中编写构造函数以获取UserUtil参数吗？我试图将mock放在测试方法中，因此：

UserUtil=Mockito.mock（UserUtil.class）；KpiServiceImpl kpiService=新的KpiServiceImpl（userUtil）但构造函数部分显示为错误。是的，您应该这样做。它使依赖项显式化，并允许轻松注入Mock，而不必依赖反射和Mock注释。