java - 在单元测试 Controller 时模拟 Spring Validator

Question

在为另一个项目创建的代码编写单元测试事后分析时，我遇到了如何模拟使用 initBinder 绑定(bind)到 Controller 的 validator 的问题？

通常我只会考虑确保我的输入有效，并在 validator 中进行一些额外的调用，但在这种情况下， validator 类与通过一些数据源进行检查相结合，这一切都变得一团糟去测试。耦合可以追溯到使用的一些旧的公共(public)库，并且不在我当前修复所有这些库的工作范围内。

起初我尝试使用 PowerMock 和模拟静态方法来模拟 validator 的外部依赖性，但最终遇到了一个在创建类时需要数据源的类，但没有找到解决该问题的方法.

然后我尝试只使用普通的 mockito 工具来模拟 validator ，但这也不起作用。然后尝试在 mockMvc 调用中设置 validator ，但这并没有为 validator 注册一个 @Mock 注释。终于碰到了this question .但是由于 Controller 本身没有 validator 字段，所以这也失败了。那么，我该如何解决这个问题呢？

validator :

public class TerminationValidator implements Validator {
    // JSR-303 Bean Validator utility which converts ConstraintViolations to Spring's BindingResult
    private CustomValidatorBean validator = new CustomValidatorBean();

    private Class<? extends Default> level;

    public TerminationValidator(Class<? extends Default> level) {
        this.level = level;
        validator.afterPropertiesSet();
    }

    public boolean supports(Class<?> clazz) {
        return Termination.class.equals(clazz);
    }

    @Override
    public void validate(Object model, Errors errors) {
        BindingResult result = (BindingResult) errors;

        // Check domain object against JSR-303 validation constraints
        validator.validate(result.getTarget(), result, this.level);

        [...]
    }

    [...]
}

Controller :

public class TerminationController extends AbstractController {

    @InitBinder("termination")
    public void initBinder(WebDataBinder binder, HttpServletRequest request) {
        binder.setValidator(new TerminationValidator(Default.class));
        binder.setAllowedFields(new String[] { "termId[**]", "terminationDate",
                "accountSelection", "iban", "bic" });
    }

    [...]
}

测试类:

@RunWith(MockitoJUnitRunner.class)
public class StandaloneTerminationTests extends BaseControllerTest {
    @Mock
    private TerminationValidator terminationValidator = new TerminationValidator(Default.class);

    @InjectMocks
    private TerminationController controller;

    private MockMvc mockMvc;

    @Override
    @Before
    public void setUp() throws Exception {
        initMocks(this);

        mockMvc = standaloneSetup(controller)
                      .setCustomArgumentResolvers(new TestHandlerMethodArgumentResolver())
                      .setValidator(terminationValidator)
                      .build();

        ReflectionTestUtils.setField(controller, "validator", terminationValidator);

        when(terminationValidator.supports(any(Class.class))).thenReturn(true);
        doNothing().when(terminationValidator).validate(any(), any(Errors.class));
    }

    [...]
}

异常:

java.lang.IllegalArgumentException: Could not find field [validator] of type [null] on target [my.application.web.controller.TerminationController@560508be]
    at org.springframework.test.util.ReflectionTestUtils.setField(ReflectionTestUtils.java:111)
    at org.springframework.test.util.ReflectionTestUtils.setField(ReflectionTestUtils.java:84)
    at my.application.web.controller.termination.StandaloneTerminationTests.setUp(StandaloneTerminationTests.java:70)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
    at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Answer 1

您应该避免在 Spring 应用程序中使用 new 创建业务对象。您应该始终从应用程序上下文中获取它们 - 这将有助于在您的测试中模拟它们。

在您的用例中，您应该简单地将 validator 创建为一个 bean(比如 defaultTerminationValidator)并将其注入(inject)到您的 Controller 中:

public class TerminationController extends AbstractController {

    private TerminationValidator terminationValidator;

    @Autowired
    public setDefaultTerminationValidator(TerminationValidator validator) {
        this.terminationValidator = validator;
    }

    @InitBinder("termination")
    public void initBinder(WebDataBinder binder, HttpServletRequest request) {
        binder.setValidator(terminationValidator);
        binder.setAllowedFields(new String[] { "termId[**]", "terminationDate",
                "accountSelection", "iban", "bic" });
    }

    [...]
}

这样，您就可以简单地在测试中注入(inject)模拟。