Jhipster - JpaRepository "principal.username" query - Error in Test

I have an error while I am testing my rest controller on a specific method. I am using the @Query annotation to do my database query. And it's using the "principal.username" to do it. I don't have the all picture on how principal.username is fetched and used in my application. I am currently looking at the spring-security documentation about it. But my problem is in the test part, when I execute the test below, I have an error "Faillure" because of the @Query.

The repository:

public interface MeetingRepository extends JpaRepository<Meeting,Long {

  @Query("select m from Meeting m where m.visibility = 'PUBLIC' OR m.user.login = ?#{principal.username}")
  Page<Meeting> findOpenAndUserMeetings(Pageable pageable);

}

A Rest Controller Method:

@RequestMapping(value = "/api/meetings",
        method = RequestMethod.GET,
        produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<List<Meeting>> getAll(@RequestParam(value = "page" , required = false) Integer offset,
                              @RequestParam(value = "per_page", required = false) Integer limit)
    throws URISyntaxException {
    Page<Meeting> page = MeetingRepository.findOpenAndUserMeetings(PaginationUtil.generatePageRequest(offset, limit));
    HttpHeaders headers = PaginationUtil.generatePaginationHttpHeaders(page, "/api/meetings", offset, limit);
    return new ResponseEntity<List<Meeting>>(page.getContent(), headers, HttpStatus.OK);
}

A test:

@Test
@Transactional
public void getAllMeetings() throws Exception {
    // Initialize the database
    MeetingRepository.saveAndFlush(Meeting);

    // Get all the Meetinges
    restMeetingMockMvc.perform(get("/api/meetings"))
            .andExpect(status().isOk())
            .andExpect(content().contentType(MediaType.APPLICATION_JSON));
}

And this error:

getAllMeetings(com.vallois.valcrm.web.rest.MeetingResourceTest)  Time elapsed: 0.07 sec  <<< ERROR!
    org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 10): Property or field 'username' cannot be found on object of type 'java.lang.String' - maybe not public?
        at org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:226)
        at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:93)
        at org.springframework.expression.spel.ast.PropertyOrFieldReference.access$000(PropertyOrFieldReference.java:46)
        at org.springframework.expression.spel.ast.PropertyOrFieldReference$AccessorLValue.getValue(PropertyOrFieldReference.java:372)
        at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:88)
        at org.springframework.expression.spel.ast.SpelNodeImpl.getTypedValue(SpelNodeImpl.java:131)
        at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:299)
        at org.springframework.data.jpa.repository.query.SpelExpressionStringQueryParameterBinder.evaluateExpression(SpelExpressionStringQueryParameterBinder.java:131)
        at org.springframework.data.jpa.repository.query.SpelExpressionStringQueryParameterBinder.potentiallyBindExpressionParameters(SpelExpressionStringQueryParameterBinder.java:89)
        at org.springframework.data.jpa.repository.query.SpelExpressionStringQueryParameterBinder.bind(SpelExpressionStringQueryParameterBinder.java:69)
        at org.springframework.data.jpa.repository.query.AbstractStringBasedJpaQuery.doCreateCountQuery(AbstractStringBasedJpaQuery.java:109)
        at org.springframework.data.jpa.repository.query.AbstractJpaQuery.createCountQuery(AbstractJpaQuery.java:190)
        at org.springframework.data.jpa.repository.query.JpaQueryExecution$PagedExecution.doExecute(JpaQueryExecution.java:173)
        at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:74)
        at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:97)
        at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:88)
        at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:395)
        at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:373)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodIntercceptor.invoke(CrudMethodMetadataPostProcessor.java:122)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
        at com.sun.proxy.$Proxy148.findOpenAndUserMeetings(Unknown Source)
        at com.vallois.valcrm.web.rest.MeetingResource.getAll(MeetingResource.java:77)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
        at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:65)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
        at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:167)
        at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:134)
        at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:144)
        at com.vallois.valcrm.web.rest.MeetingResourceTest.getAllMeetings(MeetingResourceTest.java:151)