feat : 관련 테스트 케이스 추가

Author: EpicFn

src/test/java/org/tuna/zoopzoop/backend/domain/space/membership/service/NotificationServiceTest.java

@@ -0,0 +1,45 @@
+package org.tuna.zoopzoop.backend.domain.space.membership.service;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.transaction.annotation.Transactional;
+import org.tuna.zoopzoop.backend.domain.SSE.service.EmitterService;
+
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+@ActiveProfiles("test")
+@SpringBootTest
+@Transactional
+@ExtendWith(MockitoExtension.class)
+class NotificationServiceTest {
+    @Mock
+    private EmitterService emitterService;
+
+    @InjectMocks
+    private NotificationService notificationService;
+
+    @Test
+    @DisplayName("초대 알림 전송 시 EmitterService의 sendNotification이 올바르게 호출됨")
+    void sendSpaceInvitation_CallsEmitterService() {
+        // given (준비)
+        Long memberId = 1L;
+        String testData = "test data";
+
+        // when (실행)
+        notificationService.sendSpaceInvitation(memberId, testData);
+
+        // then (검증)
+        // EmitterService의 sendNotification 메소드가
+        // memberId, "space-invitation", testData 파라미터로
+        // 1번 호출되었는지 검증
+        verify(emitterService, times(1)).sendNotification(memberId, "space-invitation", testData);
+    }
+
+}