用PowerMock spy mock private方法

在实际的工作中，经常碰到只需要mock一个类的一部分方法，这时候可以用spy来实现。

被测类：

public class EmployeeService {

    public boolean exist(String userName) {
        checkPrivateExist(userName);
        checkPublicExist(userName);
        return true;
    }

    private void checkPrivateExist(String userName) {
        throw new UnsupportedOperationException();
    }
    
    public void checkPublicExist(String userName){
        throw new UnsupportedOperationException();
    }
}

如果要测试exist方法，需要mock　checkPublicExist和checkPrivateExist方法，而不希望mock　exist方法

测试类：

@PrepareForTest(EmployeeService.class)
public class EmployeeServiceTestWithPrivateTest  extends PowerMockTestCase{
    
    @ObjectFactory
    public ITestObjectFactory getObjectFactory() {
        return new PowerMockObjectFactory();
    }

    @Test
    public void testExist() {
        try {
            EmployeeService service = PowerMockito.spy(new EmployeeService());
            PowerMockito.doNothing().when(service,"checkPrivateExist","powermock");
            PowerMockito.doNothing().when(service).checkPublicExist("powermock");;
            boolean result = service.exist("powermock");
            Assert.assertTrue(result);
            Mockito.verify(service).checkPublicExist("powermock");
            PowerMockito.verifyPrivate(service).invoke("checkPrivateExist","powermock");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

在测试类中，真实的调用了exist方法。

需要注意的是对private方法的mock

PowerMockito.doNothing().when(service,"checkPrivateExist","powermock");

以及对exist方法调用过程的验证

Mockito.verify(service).checkPublicExist("powermock");
PowerMockito.verifyPrivate(service).invoke("checkPrivateExist","powermock");