Add unit tests for Rating, Notification, and Statistic components

[Copilot]

Several controllers and services lacked test coverage: RatingController, NotificationService, NotificationController, StatisticService, and StatisticController.

New Tests (19 tests across 5 files)

• RatingControllerTest — POST /rating success, GET /rating pagination, validation failures (star out of range, comment too short, invalid page)
• NotificationServiceTest — getNotifications (success + empty + user-not-found), addEmitter (valid/invalid token), createNotification
• NotificationControllerTest — GET /notifications (authenticated, empty list, unauthenticated 401)
• StatisticServiceTest — getStatistics with full data and empty/null data edge case; verifies aggregated totals (e.g. totalCustomers = active + inactive)
• StatisticControllerTest — ADMIN success, unauthenticated 401, non-admin 403

All tests follow the existing conventions: @SpringBootTest + @MockBean, @Nested HappyCase/UnHappyCase structure, @WithMockUser for auth context, Given-When-Then comments.

@Nested
class UnHappyCase {
    @Test
    @WithMockUser(username = "user@test.com", roles = {"USER"})
    void getStatistics_nonAdminUser_forbidden() throws Exception {
        mockMvc.perform(MockMvcRequestBuilders.get("/statistics"))
                .andExpect(status().isForbidden())
                .andExpect(jsonPath("internalCode").value(1004));
    }
}

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[sonarqubecloud]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud