How to write unit test for void delete method using junit and mockito?-CodePudding

public void delete(Long id){
Optional<Car> optional = CarRepository.findById(id);
if(optional.isPresent()){
    Car car = optional.get();
    car.setActionStatus("DELETE");
    CarRepository.save(car);
}
else{
    throw new CustomException("custom message");
}}

I have to write a unit test for the above delete method, here we are not deleting the record instead we are just updating the setActionStatus to delete.

CodePudding user response：

First, don't use static methods on your CarRepository, make an interface:

interface CarRepository {
  Car findById(long id);
  void save(Car car);
  ...
}

and pass an instance of this to the class you want to test:

class ClassToTest {
  public ClassToTest(CarRepository carRepository) { ... }
  ...
}

now in your test you can use a mock CarRepository:

...
@Test
void test() {
  // create the mocks we need and set up their behaviour
  CarRepository carRepository = mock(CarRepository.class);
  Car car = mock(Car.class);
  when(carRepository.findById(123)).thenReturn(car);

  // create the instance we will test and give it our mock
  ClassToTest classToTest = new ClassToTest(carRepository);
  classToTest.delete(123);

  // check that the expected methods were called
  verify(car).setActionStatus("DELETE");
  verify(carRepository).save(car);
}

CodePudding user response：

Don't use static repositories like CarRepository. Static method are difficult to mock. Use non-static methods and inject the instance of CarRepository using dependency injection. Then you can easily inject a mock object instead.

If you insist on using static methods, there are other solutions like PowerMock library. But I wouldn't recommend it.