Mockito - 方法内的模拟对象

Question

I have a method that return the list of vehicles. Like this:

 public List<Vehicle> getVehicles() {

        List<Vehicle> vehicles=vehicleDAO.getAllVehicles();

        for (Vehicle v : vehicles){//NullPointerException
            //some bussines logic...
        }       
        return vehicles;

}

And here is my test:

@Test
public void testShowVehicles() {
    when(vehicleDAO.getAllVehicles()).thenReturn(listVehiclesMock);
    List<Vehicle> vehicles= service.getVehicles();//NullPointerException
    assertEquals(listVehicleMock, vehicles);
}

When I run it I get NullPointerException because Vehicle does not exists. When I have old fashion for loop it passes the test, but now I replaced with forEach loop I get error in test. So how would I mock the object Vehicle?

Answer 1

For each loop uses iterator() method of the given Iterable . An iterator obtained that way is then used to iterate over the collection. Unfortunately, this method of the mocked list returns null, which causes NullPointerException . To use for each loop syntax you have to bind iterator() method to result as well.