Writing fast & maintainable integration tests using test double, in-memory db, jetty, maven and spring

Writing an integration test which test end to end flow of your application can become cumbersome activity if you really hitting real db and services. The best way to mock, test double your external dependencies and thus speed up your test execution.

I created a dummy map-service project which demonstrate about writing maintainable and speedy integration tests using mocking, test double pattern, spring and automating them using maven and jetty. You can find the project at my github location: https://github.com/sagarr/maps-service

Here are some code snippets explaining the important steps in configuring your project.

1. POM - Configure jetty for deploying your app and running tests against it.

.


 org.mortbay.jetty
 jetty-maven-plugin
 ${jettyVersion}
 
  
   /${project.artifactId}
  
  8005
  STOP
  5
  true
  
   
    8080
    60000
   
  
 
 
  
   start-jetty
   pre-integration-test
   
    run
   
   
    0
    true
   
  
  
   stop-jetty
   post-integration-test
   
    stop
   
  
 




 maven-failsafe-plugin
 2.12
 
  
   **/integration/**Test.java
  
 
 
  
   integration-test
  
 

.
.

2. MockBeanInjector.java - In order to test double database and service calls

public class MockBeanInjector implements BeanPostProcessor {

    private final static Logger LOG = LoggerFactory.getLogger(MockBeanInjector.class);

    @Override
    public Object postProcessBeforeInitialization(final Object bean, final String beanName) throws BeansException {
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(final Object bean, final String beanName) throws BeansException {
        if (bean instanceof DataSource) {
            LOG.info("Mocking DataSource instance: " + bean);
            final EmbeddedDatabaseBuilder embeddedDatabaseBuilder = new EmbeddedDatabaseBuilder();
            final EmbeddedDatabase embeddedDatabase =
                embeddedDatabaseBuilder.addScript("schema.sql").addScript("data.sql").build();
            return embeddedDatabase;
            // else
            // return new ClassPathXmlApplicationContext("applicationContext-test.xml").getBean("dataSource");
        }
        if (bean instanceof AuthserverGateway) {
            LOG.info("Mocking AuthserverGateway instance: " + bean);
            final AuthserverGateway mockAsGateway = mock(AuthserverGateway.class);
            final ResponseEntity response = new ResponseEntity(HttpStatus.NO_CONTENT);
            when(mockAsGateway.callAuthorizeService("12345")).thenReturn(response);
            return mockAsGateway;
        } else {
            return bean;
        }
    }
}

3. Finally tests

public class PoiWsRestClientTest {

    @Test
    public void should_create_poi() {
        // given
        final Poi poi = new Poi();
        poi.setName("Pizza Center");
        poi.setLatitude(new BigDecimal("23.23212"));
        poi.setLongitude(new BigDecimal("34.231312"));

        // when
        final URI location = new RestTemplate().postForLocation("http://localhost:8080/maps-service/pois", poi);

        // then
        assertThat(location.getPath(), endsWith("/pois/102"));
    }

    @Test
    public void should_read_poi() {
        // when
        final Poi poi = new RestTemplate().getForObject("http://localhost:8080/maps-service/pois/100", Poi.class);

        // then
        assertThat(poi.getId(), is("100"));
    }

    @Test
    public void should_delete_poi() {
        // given
        final HttpHeaders headers = new HttpHeaders();
        headers.set("Authorization", "12345");
        final HttpEntity httpEntity = new HttpEntity(headers);

        // when
        final ResponseEntity response =
            new RestTemplate().exchange("http://localhost:8080/maps-service/pois/101", HttpMethod.DELETE, httpEntity,
                String.class);

        // then
        assertThat(response.getStatusCode(), is(HttpStatus.NO_CONTENT));
    }
}