NullPointer Exception everytime I try to run my Junit Test Case - spring

Question

Every time i try to run the junit test case , i get null pointer exception and also when i tried to hadle the exception everytime the function returns NULL value. Here is the code.
RestaurantRepository.java
package org.springsource.restbucks;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Transactional;
#Component
#Transactional
public interface RestaurantRepository extends PagingAndSortingRepository<Restaurant, Long> {
#Query("SELECT p FROM Restaurant p Where (p.id)=(:Id) and p.deleted=false")
Restaurant findById(#Param("Id") long Id);
#Query("SELECT p FROM Restaurant p Where LOWER(p.name)=LOWER(:name) and p.deleted = false")
Restaurant findByName(#Param("name") String name);
}
RestaurantController.java
#RestController
public class RestaurantController {
#Autowired
RestaurantRepository repository;
#RequestMapping(value = "/restaurants/{id}", method = RequestMethod.GET, produces = {MediaType.APPLICATION_JSON_VALUE})
#ResponseStatus(HttpStatus.OK)
#ResponseBody
public ResponseEntity<Restaurant> getRestaurant(#PathVariable("id") long restaurantId) {
Restaurant responseRestaurant = repository.findOne(restaurantId);
if(responseRestaurant==null){
logger.error("No Restaurant found with id:"+restaurantId);
return new ResponseEntity<Restaurant>(HttpStatus.NOT_FOUND);
}else if(responseRestaurant.isDeleted()==true){
logger.error("Restaurant Object is deleted");
return new ResponseEntity<Restaurant>(HttpStatus.NOT_FOUND);
}else{
return new ResponseEntity<Restaurant>(responseRestaurant,HttpStatus.OK);
}
}
}
RestaurantRepositoryTest.java
import static org.junit.Assert.assertEquals;
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
public class RestaurantRepositoryTest{
#Autowired
private RestaurantRepository repository;
#Test
public void testfindById() throws Exception{ //testing findbyid method in restaurant repository
Restaurant responseRestaurant = repository.findByName("xyz"); //getting error over here
assertEquals("xyz",responseRestaurant.getName());
}
}
I am getting null pointer exception whenever i run mvn test . the stack trace is below what i get displayed in terminal.
testfindById(org.springsource.restbucks.RestaurantRepositoryTest)
Time elapsed: 0.018 sec <<< ERROR! java.lang.NullPointerException:
null at
org.springsource.restbucks.RestaurantRepositoryTest.testfindById(RestaurantRepositoryTest.java:19)
what shall i do to run my test successfully??

Answer 1

You're running that as a pure unit test with no Spring context. Therefore, the repository will not be autowired. You should be able to fix that by adding a few annotations to the top of your test class.
If using Spring Boot, then something like the following should work, to let Spring Boot do all the hard work:
#RunWith(SpringJUnit4ClassRunner.class)
#SpringApplicationConfiguration(classes = MyApplication.class)
You can alternatively load the Spring #Configuration class which would initialise your repositories (In my case, this is called DbConfig), like so:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = { DbConfig.class },
loader = AnnotationConfigContextLoader.class)

Answer 2

Your test is not starting up a Spring context at all, so the annotations are completely ignored. The best solution is to modify your controller class to take the repository as a constructor argument instead of using field injection. This allows you to pass in a simple mock, such as a Mockito mock, and avoid the complexity of starting up a Spring context to run a unit test.