java.lang.AssertionError: Expecting actual not to be null

Создал рест апи приложение и теперь начинаю учить тестирование, выдает ошибку на этот тест

import com.product.controller.ProductController;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import static org.assertj.core.api.Assertions.assertThat;


@SpringBootTest(classes = ProductController.class)
public class ProductControllerTest {

    @Autowired
    private ProductController productController;

    @Test
    public void test() throws Exception{
     (20 строка)  assertThat(productController).isNotNull();
    }
}

все сделал как говорится на сайте spring.io, но пишет что тест провален

controller

@RestController
@RequestMapping(value = "/product/")
public class ProductController {

    @Autowired
    ProductService productService;

@RequestMapping(value = "",method = RequestMethod.GET,produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
    public ResponseEntity<List<Product>> getAllProducts(){
        List<Product> products = this.productService.getAll();

       if (products.isEmpty()){
            return new ResponseEntity<>(HttpStatus.NOT_FOUND);
        }

        return new ResponseEntity<>(products,HttpStatus.OK);
    }
}

pom

    <!-- Testing -->
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>5.5.2</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <version>2.2.3.RELEASE</version>
            <scope>test</scope>
        </dependency>

сервис класс

public interface ProductService {

    Product getById(BigInteger _id);

    void save(Product product);

    List<Product> getAll();

    List<Long> getAllCategoryIds();

}

@Service
public class ProductServiceImpl implements ProductService {

    @Autowired
    ProductRepository productRepository;

    @Autowired
    CategoryIdRepository categoryIdRepository;

    @Override
    public Product getById(BigInteger _id) {
       return productRepository.findOne(_id);
    }

    @Override
    public void save(Product product) {
        productRepository.save(product);
    }

    @Override
    public List<Product> getAll(){
        return productRepository.findAll();
    }

    @Override
    public List<Long> getAllCategoryIds() {
        return categoryIdRepository.findAllId();
    }

}