In this post, I will show how we can add integration testing to a Spring Boot application.

Integration tests play a key role in ensuring the quality of the application. With a framework like Spring Boot, it is even easier to integrate such tests. Nevertheless, it is important to test applications with integration tests without deploying them to the application server.

Integration tests can help to test the data access layer of your application. Integration tests also help to test multiple units. For the Spring Boot application, we need to run an application in ApplicationContext to be able to run tests. Integration tests can help in testing exception handling.

Spring Boot Application

For this demo, we will build a simple Spring Boot application with REST APIs. We will be using the H2 In-Memory database for storing the data. Eventually, I will show how to write an integration test. This application reads a JSON file of vulnerabilities from the National Vulnerability Database and stores it in the H2 database. REST APIs allow a user to fetch that data in a more readable format.

Dependencies

First, we want to build integration tests in this application, so we will need to include the dependency spring-boot-starter-test .

dependencies {
 implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
 implementation 'org.springframework.boot:spring-boot-starter-web'
 implementation 'junit:junit:4.13.1'
 runtimeOnly 'com.h2database:h2:1.4.200'
 testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

This dependency of spring-boot-starter-test allow us to add testing-related annotations that we will see soon.

REST API

Now as I said previously, we will have a REST API to fetch national vulnerability database data. We will create a REST controller with two APIs one to fetch a list of vulnerabilities and one to fetch a vulnerability by CVE id.

@RestController
@RequestMapping("/v1/beacon23/vulnerabilities")
public class CveController
{

    @Autowired
    private CveService cveService;

    @GetMapping("/list")
    public List getAllCveItems(@RequestParam(required = false, name="fromDate") String fromDate, @RequestParam(required = false, name=
            "toDate") String toDate)
    {
        List cveDTOList = cveService.getCveItems(fromDate, toDate);

        if(cveDTOList == null || cveDTOList.isEmpty())
        {
            return new ArrayList<>();
        }
        else
        {
            return cveDTOList;
        }
    }

    @GetMapping
    public ResponseEntity getCveItemById(@RequestParam("cveId") String cveId)
    {
        CveDTO cveDTO = cveService.getCveItemByCveId(cveId);

        if(cveDTO != null)
        {
            return new ResponseEntity<>(cveDTO, HttpStatus.OK);
        }
        else
        {
            return new ResponseEntity<>(HttpStatus.NO_CONTENT);
        }
    }

}

So we have

• /v1/beacon23/vulnerabilities/list – to fetch a list of vulnerabilities
• /v1/beacon23/vulnerabilities?cveId=value – to fetch vulnerability by CVE id.

Service

Now, most of the business logic and validation happen in Service class. As we saw in our API, we use CVEService to fetch the required data.

    @Autowired
    public CveDataDao cveDataDao;

    public List getCveItems(String from, String to)
    {
        LOGGER.debug("The date range values are from = {} and to = {}", from, to);
        List cveDataList = cveDataDao.findAll();
        List cveDTOList = new ArrayList<>();

        for(CveData cveData : cveDataList)
        {
            List cveList = cveData.getCveItems();
            for(CveItem cveItem: cveList)
            {
                Date fromDate;
                Date toDate;

                if(!isNullOrEmpty(from) && !isNullOrEmpty(to))
                {
                    fromDate = DateUtil.formatDate(from);
                    toDate = DateUtil.formatDate(to);

                    Date publishedDate = DateUtil.formatDate(cveItem.getPublishedDate());

                    if(publishedDate.after(toDate) || publishedDate.before(fromDate))
                    {
                        continue;
                    }
                }
                CveDTO cveDTO = convertCveItemToCveDTO(cveItem);
                cveDTOList.add(cveDTO);
            }
        }
        return cveDTOList;
    }

    private boolean isNullOrEmpty (String str)
    {
        return (str == null || str.isEmpty());
    }

    private String buildDescription (List descriptionDataList)
    {
        if(descriptionDataList == null || descriptionDataList.isEmpty())
        {
            return EMPTY_STRING;
        }
        else
        {
            return descriptionDataList.get(0).getValue();
        }
    }

    private List buildReferenceUrls (List referenceDataList)
    {
        return referenceDataList.stream().map(it -> it.getUrl()).collect(Collectors.toList());
    }

    public CveDTO getCveItemByCveId(String cveId)
    {
        List cveDataList = cveDataDao.findAll();
        CveDTO cveDTO = null;

        for(CveData cveData : cveDataList)
        {
            List cveItems = cveData.getCveItems();

            Optional optionalCveItem =
                    cveItems.stream().filter(ci -> ci.getCve().getCveMetadata().getCveId().equals(cveId)).findAny();
            CveItem cveItem = null;
            if(optionalCveItem.isPresent())
            {
                cveItem = optionalCveItem.get();
            }
            else
            {
                return cveDTO;
            }
            cveDTO = convertCveItemToCveDTO(cveItem);
        }

        return cveDTO;
    }

Usage of @SpringBootTest

Spring Boot provides an annotation @SpringBootTest that we can use in integration tests. With this annotation, the tests can start the application context that can contain all the objects we need for the application to run.

Integration tests provide an almost production-like scenario to test our code. The tests annotated with @SpringBootTest create the application context used in our tests through application class annotated with @SpringBootConfiguration.

These tests start an embedded server, create a web environment, and then run @Test methods to do integration testing. We need to add few attributes to make sure we can start web environment while using @SpringBootTest.

• Attribute webEnvironment – To create a web environment with a default port or a random port.

We can also pass properties to use for tests using an active profile. Usually, we use these profiles for different environments, but we can also use a special profile for tests only. We create application-dev.yml, application-prod.yml profiles. Similarly, we can create application-test.yml and use the annotation @ActiveProfiles('test') in our tests.

Example of Integration Test

For our REST API, we will create an integration test that will test our controller. We will also use TestRestTemplate to fetch data. This integration test will look like below:

package com.betterjavacode.beacon23.tests;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.boot.web.server.LocalServerPort;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.test.context.junit4.SpringRunner;

import static org.junit.Assert.assertNotNull;

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class CveControllerTest
{
    @LocalServerPort
    private int port;

    TestRestTemplate testRestTemplate = new TestRestTemplate();

    HttpHeaders headers = new HttpHeaders();

    @Test
    public void testGetAllCveItems()
    {
        HttpEntity entity = new HttpEntity<>(null, headers);

        ResponseEntity responseEntity = testRestTemplate.exchange(createURLWithPort(
                "/v1/beacon23/vulnerabilities/list"),HttpMethod.GET, entity, String.class);

        assertNotNull(responseEntity);

    }


    private String createURLWithPort(String uri)
    {
        return "http://localhost:" + port + uri;
    }
}

We use @SpringBootTest annotation for our test class and set up the application context by using webEnvironment with a RANDOM_PORT. We also mock the local web server by setting up a mock port with @LocalServerPort.

TestRestTemplate allows us to simulate a client that will call our API. Once we run this test (either through gradle build OR through IntelliJ), we will see the Spring Boot Application Context setup running and the application running at a random port.

One disadvantage of creating integration tests with @SpringBootTest is that it will slow down building your application. In most enterprise environments, you will have this set up through continuous integration and continuous deployment. In such scenarios, it slows down the process of integration and deployment if you have a lot of integration tests.

Conclusion

Finally, you should use integration testing in the Spring Boot application or not, it depends on your application. But despite the drawback, it is always useful to have integration tests that allow testing multiple units at a time. @SpringBootTest is a handy annotation that can be used to set up an application context, allowing us to run tests close to a production environment.

References

1. integration Testing with Spring Boot – Integration Testing

In this post, I will show how we can use the annotation @ControllerAdvice – Controller Advice – an exception handler in the Spring Boot application. If you want to read how to handle uncaught exceptions in Spring Boot, you can check my old post.

What is @ControllerAdvice ?

Spring 3.2 introduced an annotation @ControllerAdvice. The annotation allows the handling of exceptions across the application. Before this, Spring offered another annotation @ExceptionHandler for exception handling. But, you have to add this annotation in each controller class of your application. It doesn’t help on the application level.

@ControllerAdvice is an annotation-driven interceptor. It intercepts most of those classes that include @RequestMapping.

Comparison with @ExceptionHandler

In most controller classes, you can add @ExceptionHandler annotation to handle exceptions for that class. Nevertheless, in such classes, one can add an extra method to handle exceptions thrown by @RequestMapping methods in the same controller. These exception handling methods can redirect the user to the error page OR build a custom error response.

This will look like below:

@RestController
@RequestMapping("/companies")
public class CompanyController
{
  
  @GetMapping
  public List<Company> getAllCompanies(HttpServletRequest req) throws Exception {
    
  } 
  @ExceptionHandler(Exception.class)
  public ModelAndView handleError(HttpServletRequest req, Exception ex) {
    logger.error("Request: " + req.getRequestURL() + " raised " + ex);

    ModelAndView mav = new ModelAndView();
    mav.addObject("exception", ex);
    mav.addObject("url", req.getRequestURL());
    mav.setViewName("error");
    return mav;
  }

}

Additionally, you can see the method getAllCompanies throw an Exception. The method handleError will handle the exception thrown by getAllCompanies.

Furthermore, if I have another controller like UserController, I will end up writing like below if it has to handle exceptions.

@RestController
@RequestMapping("/users")
public class UserController
{
  
  @GetMapping
  public List<User> getAllUsers(HttpServletRequest req) throws Exception {
    
  } 
  @ExceptionHandler(Exception.class)
  public ModelAndView handleError(HttpServletRequest req, Exception ex) {
    logger.error("Request: " + req.getRequestURL() + " raised " + ex);

    ModelAndView mav = new ModelAndView();
    mav.addObject("exception", ex);
    mav.addObject("url", req.getRequestURL());
    mav.setViewName("error");
    return mav;
  }

}

Henceforth, this makes a lot of duplicate code. This is where Controller Advice comes into the picture with an advantage.

Example of Controller Advice

A Controller Advice allows you to use the same exception handling technique across applications, without repeating any code.

Consequently, a class annotated with @ControllerAdvice implements three types of methods:

• Exception handling method annotated with @ExceptionHandler
• Model enhancement methods annotated with @ModelAttribute
• Binder initialization methods annotated with @InitBinder

 

@ControllerAdvice
public class GlobalExceptionHandler
{
   
    @ExceptionHandler(CompanyNotFoundException.class)
    public ModelAndView handleError(HttpServletRequest req, CompanyNotFoundException ex) 
    {
       logger.error("Request: " + req.getRequestURL() + " raised " + ex);

       ModelAndView mav = new ModelAndView();
       mav.addObject("exception", ex);
       mav.addObject("url", req.getRequestURL());
       mav.setViewName("error");
       return mav;
     }

    @ExceptionHandler(UserNotFoundException.class)
    public ResponseEntity handleUserExceptionError(HttpServletRequest req, HttpServletResponse res, UserNotFoundException ex)
    {
       List errors = Collections.singletonList(ex.getMessage());
       // Get headers
       if(HttpStatus.INTERNAL_SERVER_ERROR.equals(res.getStatus()))
       {
         // do something
       } 

       return new ResponseEntity<>(new ApiError(errors), headers, status);
    }

}

This will allow now to intercept any exception thrown from controllers. This makes implementing exception handling easier.

Conclusion

In this post, I showed how we can implement Controller Advice – exception handler in Spring Boot. This is a very effective way to handle exceptions in the current applications built with Spring Boot.