ValidationTestLaimonas

 @Test
    void validationTest() throws Exception {
        Notification notification = new Notification("", "", null, "", "");
        MvcResult mvcResult = mockMvc
                .perform(post("/notifyUser")
                        .contentType(MediaType.APPLICATION_JSON)
                        .content(objectMapper.writeValueAsString(notification))
                )
                .andExpect(status().isBadRequest())
                .andReturn();

        String contentAsString = mvcResult.getResponse().getContentAsString();
        assertThat(contentAsString).contains("activityId is mandatory and cannot be null");
        assertThat(contentAsString).contains("targetId is mandatory and cannot be blank");
        assertThat(contentAsString).contains("userId is mandatory and cannot be blank");
        assertThat(contentAsString).contains("type is mandatory and cannot be blank");
        assertThat(contentAsString).contains("userId is mandatory and cannot be blank");
    }