Unit testing in spring boot - unit-testing

Question

I am very new to Spring Boot and trying to learn how testing should be done in Spring Boot. I read about the #SpringBootTest annotation which helps in integration testing an application. I was wondering how unit testing should be done in spring boot. Does unit testing require specifying the #SpringBootTest annotation or is that to be used only for integration testing? Are there specific annotations to be used for unit testing?
Any pointers would be much appreciated. Thanks in advance!
Edit:
Is the SpringBootTest annotation used only for integration testing? I found the following code example in the Spring documentation:
#RunWith(SpringRunner.class)
#SpringBootTest
#AutoConfigureMockMvc
public class HelloControllerTest {
#Autowired
private MockMvc mvc;
#Test
public void getHello() throws Exception {
mvc.perform(MockMvcRequestBuilders.get("/").accept(MediaType.APPLICATION_JSON))
.andExpect(status().isOk())
.andExpect(content().string(equalTo("Greetings from Spring Boot!")));
}
}
Is this a unit or integration test? My guess is its not an integration test since it uses a MockMvc. Is that right? If so, does this mean that the #SpringBootTest annotation can be used for tests which are not full fledged integration tests?

Answer 1

Strictly speaking, "unit" tests should not use Spring. Just use JUnit/TestNG/Spock/whatever, like you normally would, to test the individual classes. #SpringBootTest is for integration, and beyond, tests.

Answer 2

This is what I would do:
For Integration Testing end-to-end:
#RunWith(SpringRunner.class)
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class ApplicationTests {
#Autowired
private TestRestTemplate restTemplate;
#Autowired
private CarRepository repository;
#Autowired
private CarService carService;
#Test
public void contextLoads() {
}
#Test
public void basicTest() {
String body = this.restTemplate.getForObject("/", String.class);
assertThat(body).contains("Not Found");
}
}
For testing a controller only (controller unit test):
#RunWith(SpringRunner.class)
#WebMvcTest(controllers = CarController.class, excludeAutoConfiguration = EmbeddedMongoAutoConfiguration.class)
public class ControllerTests {
#Autowired
private MockMvc mvc;
#MockBean
private CarRepository carRepository;
#MockBean
private MongoTemplate mongoTemplatel;
#Test
public void testGet() throws Exception {
short year = 2010;
given(this.carRepository.findByVin("ABC"))
.willReturn(new Car("ABC", "Honda", "Accord", year, 100000, "Red", "Ex-V6"));
this.mvc.perform(get("/car").param("VIN", "ABC").accept(MediaType.APPLICATION_JSON))
.andExpect(status().isOk()).andExpect(content().string("[{\"vin\":\"ABC\",\"make\":\"Honda\",\"model\":\"Accord\",\"year\":2010,\"mileage\":100000,\"color\":\"Red\",\"trim\":\"Ex-V6\",\"type\":null,\"maintenanceTasksList\":[\"Oil Change\",\"Tire Rotation\"]}]"));
}
}
You can find a complete Spring Boot application that include Integration and Unit tests here.