API 테스트 에러처리 수정

src/main/java/com/eactive/httpmockserver/client/service/NettyApiClient.java

@@ -98,6 +98,16 @@ public class NettyApiClient {
 
             ch.writeAndFlush(request);
             ch.closeFuture().sync();
+        } catch (Exception e) {
+            ApiResponse response = new ApiResponse();
+            if (e instanceof java.net.UnknownHostException) {
+                response.setStatus(404);
+                response.setBody("Unknown host: " + e.getMessage());
+            } else {
+                response.setStatus(500);
+                response.setBody("An error occurred: " + e.getMessage());
+            }
+            return CompletableFuture.completedFuture(response);
         } finally {
             group.shutdownGracefully();
         }