How to get Database connection in Spring using JUnit?

I'm trying to test the correct information given from DB using the services and the correct logic of the methods. In this simple example, I'm only using the statement assertEquals to compare the id given for the roleService, but I'm still getting errors. I have the following code:

[UPDATED]

Test method:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(value = { "classpath:applicationContext.xml" })
@Transactional
@WebAppConfiguration
@ComponentScan(basePackages ={ "com.project.surveyengine" },
            excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION, value = Configuration.class) ,
                              @ComponentScan.Filter(type = FilterType.ANNOTATION, value = WebConfig.class)})
public class RoleServiceTest {

@Configuration
    static class ContextConfiguration {    
        @Bean
        public RoleService roleService() {
            RoleService roleService = new RoleService();
            // set properties, etc.
            return roleService;
        }
    }

    private final LocalServiceTestHelper helper =
            new LocalServiceTestHelper(new LocalDatastoreServiceTestConfig()
                    .setDefaultHighRepJobPolicyUnappliedJobPercentage(100));

    private Closeable closeable;

    @Before
    public void setUp() {
        helper.setUp();
        ObjectifyService.register(Role.class);
        closeable = ObjectifyService.begin();
    }

    @After
    public void tearDown() {
        closeable.close();
        helper.tearDown();
    }

    @Autowired
    private RoleService roleService;

    @Test
    public void existsRole() throws Exception{
        Role role = roleService.getByName("ROLE_ADMIN");
        assertEquals("Correct test", Long.valueOf("5067160539889664"), role.getId());
    }

}

RoleService is the service class that consult Database information using objectifyService from Google App Engine.

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:annotation-config /> 

    <context:component-scan base-package="com.project.surveyengine.config"/>

    <!--Controllers-->
    <bean id="inboxController" class="com.project.surveyengine.controller.InboxController" autowire="byType"></bean>
    <bean id="mailController" class="com.project.surveyengine.controller.MailController" autowire="byType"></bean>
    <bean id="loginController" class="com.project.surveyengine.controller.LoginController" autowire="byType"></bean>
    <bean id="initController" class="com.project.surveyengine.controller.InitController" autowire="byType"></bean>

    <!--Services-->
    <bean id="answerService" class="com.project.surveyengine.service.impl.AnswerService" autowire="byType"></bean>
    <bean id="blobService" class="com.project.surveyengine.service.impl.BlobService" autowire="byType"></bean>
    <bean id="mailService" class="com.project.surveyengine.service.impl.MailService" autowire="byType"></bean>
    <bean id="caseService" class="com.project.surveyengine.service.impl.CaseService" autowire="byType"></bean>
    <bean id="roleService" class="com.project.surveyengine.service.impl.RoleService" autowire="byType"></bean>
</beans>

Into the com.project.surveyengine.config I have the folliwing three classes:

1)

public class MyXmlWebApplicationContext extends XmlWebApplicationContext {
    protected void initBeanDefinitionReader(XmlBeanDefinitionReader beanDefinitionReader) {
        super.initBeanDefinitionReader(beanDefinitionReader);
        if (SystemProperty.environment.value() == SystemProperty.Environment.Value.Production) {
            beanDefinitionReader.setValidating(false);
            beanDefinitionReader.setNamespaceAware(true);
        }
    }
}

2)

@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter{    
  @Bean
  UrlBasedViewResolver resolver(){
    UrlBasedViewResolver resolver = new UrlBasedViewResolver();
    resolver.setPrefix("/views/");
    resolver.setSuffix(".jsp");
    resolver.setViewClass(JstlView.class);
    return resolver;
  }

  @Override
  public void addResourceHandlers(ResourceHandlerRegistry registry) {
    registry.addResourceHandler("/statics/**").addResourceLocations("/statics/");
  }    
}

3)

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class SecurityContext extends WebSecurityConfigurerAdapter {    
    @Override
    public void configure(WebSecurity web) throws Exception {
        web.ignoring().antMatchers("/statics/**");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .formLogin()
                //...more code
    }
}

I'm getting this errors:

Dec 20, 2016 4:40:03 PM com.google.appengine.api.datastore.dev.LocalDatastoreService init INFO: Local Datastore initialized: Type: High Replication Storage: In-memory

java.lang.NullPointerException at com.project.surveyengine.service.impl.RoleServiceTest.existsRole(RoleServiceTest.java:111)

RoleServiceTest.java:111 = assertEquals("Correct test", Long.valueOf("5067160539889664"), role.getId());