Тесты с созданным мапером:
@Test
public void shouldMapCarToDto() {
//given
Car car = new Car("Morris", 5, CarType.SEDAN);
//when
CarDto carDto = CarMapper.INSTANCE.carToCarDto(car);
//then
assertThat(carDto).isNotNull();
assertThat(carDto.getMake()).isEqualTo("Morris");
assertThat(carDto.getSeatCount()).isEqualTo(5);
assertThat(carDto.getType()).isEqualTo("SEDAN");
}