java - 外部模拟方法在实际类中返回 Null

Question

当我测试模拟外部调用时，我没有看到报告的模拟值，而是 Null 并且我的测试失败。我可以在测试类中看到(报告的)模拟值，但在 BusinessServiceImpl 类中看不到，并且应用程序(方法返回)未按我的预期进行修改。

我的期望:当我在 Impl 类中模拟外部调用时，模拟值应该在那里可用，并且其他所有事情都会发生，就像调用真实方法来完成单元测试一样。

实现代码:

package com.core.business.service.dp.fulfillment;

import com.core.business.service.dp.payment.PaymentBusinessService;

public class BusinessServiceImpl implements BusinessService { // Actual Impl Class
    private PaymentBusinessService paymentBusinessService = PluginSystem.INSTANCE.getPluginInjector().getInstance(PaymentBusinessService.class);

    @Transactional( rollbackOn = Throwable.class)
    public Application  applicationValidation (final Deal deal) throws BasePersistenceException {
        Application application = (Application) ApplicationDTOFactory.eINSTANCE.createApplication();
        //External Call we want to Mock
        String report = paymentBusinessService.checkForCreditCardReport(deal.getId());
        if (report != null) {
            application.settingSomething(true); //report is Null and hence not reaching here
        }
        return application;
    }
}

测试代码:

@Test(enabled = true)// Test Class
public void testReCalculatePrepaids() throws Exception {
    PaymentBusinessService paymentBusinessService = mock(PaymentBusinessService.class);
    //Mocking External Call
    when(paymentBusinessService.checkForCreditCardReport(this.deal.getId())).thenReturn(new String ("Decline by only Me"));
    String report = paymentBusinessService.checkForCreditCardReport(this.deal.getId());
    // Mocked value of report available here
    //Calling Impl Class whose one external call is mocked
    //Application is not modified as expected since report is Null in Impl class
    Application sc = BusinessService.applicationValidation(this.deal);
}

Answer 1

Mockito 的主要目的是隔离测试。例如，当您测试 BusinessServiceImpl 时，您应该模拟其所有依赖项。

这正是您在上面的示例中尝试执行的操作。现在，为了让模拟发挥作用，必须将模拟对象注入(inject)到您尝试测试的类中，在本例中为 BusinessServiceImpl。

实现此目的的一种方法是通过类的构造函数 dependency injection 传递依赖关系。 。或者你可以看看如何用 Spring and ReflectionTestUtils. 来完成