KL-64/test: create response advice test

- global response advice 테스트코드 추가

src/test/java/taco/klkl/global/response/GlobalResponseAdviceTest.java

@@ -0,0 +1,105 @@
+package taco.klkl.global.response;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.server.ServerHttpRequest;
+import org.springframework.http.server.ServletServerHttpResponse;
+import org.springframework.mock.web.MockHttpServletResponse;
+
+class GlobalResponseAdviceTest {
+
+	private GlobalResponseAdvice advice;
+
+	@Mock
+	private ServerHttpRequest request;
+
+	@Mock
+	private ServletServerHttpResponse response;
+
+	@BeforeEach
+	void setUp() {
+		MockitoAnnotations.openMocks(this);
+		advice = new GlobalResponseAdvice();
+	}
+
+	@Test
+	@DisplayName("supports 메소드가 항상 true를 반환하는지 확인")
+	void testSupports() {
+		assertTrue(advice.supports(null, null));
+	}
+
+	@Test
+	@DisplayName("성공 상태 코드(2xx)에 대해 GlobalResponse 객체를 반환하는지 확인")
+	void testBeforeBodyWrite_WithSuccessStatus() {
+		// Given
+		Object body = new Object();
+		MockHttpServletResponse mockResponse = new MockHttpServletResponse();
+		mockResponse.setStatus(HttpStatus.OK.value());
+		when(response.getServletResponse()).thenReturn(mockResponse);
+
+		// When
+		Object result = advice.beforeBodyWrite(body, null, MediaType.APPLICATION_JSON, null, request, response);
+
+		// Then
+		assertTrue(result instanceof GlobalResponse);
+		GlobalResponse globalResponse = (GlobalResponse)result;
+		assertEquals("C000", globalResponse.code());
+		assertEquals(body, globalResponse.data());
+	}
+
+	@Test
+	@DisplayName("오류 상태 코드에 대해 원본 body를 그대로 반환하는지 확인")
+	void testBeforeBodyWrite_WithErrorStatus() {
+		// Given
+		Object body = new Object();
+		MockHttpServletResponse mockResponse = new MockHttpServletResponse();
+		mockResponse.setStatus(HttpStatus.BAD_REQUEST.value());
+		when(response.getServletResponse()).thenReturn(mockResponse);
+
+		// When
+		Object result = advice.beforeBodyWrite(body, null, MediaType.APPLICATION_JSON, null, request, response);
+
+		// Then
+		assertEquals(body, result);
+	}
+
+	@Test
+	@DisplayName("body가 String 타입일 때 원본 body를 그대로 반환하는지 확인")
+	void testBeforeBodyWrite_WithStringBody() {
+		// Given
+		String body = "Test String";
+		MockHttpServletResponse mockResponse = new MockHttpServletResponse();
+		mockResponse.setStatus(HttpStatus.OK.value());
+		when(response.getServletResponse()).thenReturn(mockResponse);
+
+		// When
+		Object result = advice.beforeBodyWrite(body, null, MediaType.APPLICATION_JSON, null, request, response);
+
+		// Then
+		assertEquals(body, result);
+	}
+
+	@Test
+	@DisplayName("HttpStatus가 null일 때 (즉, 유효하지 않은 상태 코드) 원본 body를 그대로 반환하는지 확인")
+	void testBeforeBodyWrite_WithNullHttpStatus() {
+		// Given
+		Object body = new Object();
+		MockHttpServletResponse mockResponse = new MockHttpServletResponse();
+		mockResponse.setStatus(999); // Invalid status code
+		when(response.getServletResponse()).thenReturn(mockResponse);
+
+		// When
+		Object result = advice.beforeBodyWrite(body, null, MediaType.APPLICATION_JSON, null, request, response);
+
+		// Then
+		assertEquals(body, result);
+	}
+}