✅ test: SSE 최초 접속 테스트 코드 작성

server/package.json

@@ -55,6 +55,7 @@
     "@nestjs/schematics": "^10.0.0",
     "@nestjs/testing": "^10.0.0",
     "@types/cookie-parser": "^1.4.7",
+    "@types/eventsource": "^1.1.15",
     "@types/express": "^5.0.0",
     "@types/jest": "^29.5.2",
     "@types/lodash": "^4.17.13",
@@ -67,6 +68,7 @@
     "eslint": "^9.0.0",
     "eslint-config-prettier": "^9.0.0",
     "eslint-plugin-prettier": "^5.0.0",
+    "eventsource": "^2.0.2",
     "ioredis-mock": "^8.9.0",
     "jest": "^29.5.0",
     "prettier": "^3.0.0",

server/test/feed/trend.e2e-spec.ts

@@ -0,0 +1,102 @@
+import { INestApplication } from '@nestjs/common';
+import { EventEmitter } from 'stream';
+import { RedisService } from '../../src/common/redis/redis.service';
+import { redisKeys } from '../../src/common/redis/redis.constant';
+import { RssAcceptFixture } from '../fixture/rssAccept.fixture';
+import { FeedRepository } from '../../src/feed/feed.repository';
+import { RssAcceptRepository } from '../../src/rss/rss.repository';
+import { Feed } from '../../src/feed/feed.entity';
+import { FeedFixture } from '../fixture/feed.fixture';
+import * as EventSource from 'eventsource';
+
+describe('SSE /api/trend/sse E2E Test', () => {
+  let app: INestApplication;
+  let feedRepository: FeedRepository;
+
+  beforeAll(async () => {
+    app = global.testApp;
+    feedRepository = app.get(FeedRepository);
+    const rssAcceptRepository = app.get(RssAcceptRepository);
+    const redisService = app.get(RedisService);
+    const [blog] = await Promise.all([
+      rssAcceptRepository.save(RssAcceptFixture.createRssAcceptFixture()),
+      redisService.redisClient.rpush(redisKeys.FEED_ORIGIN_TREND_KEY, 1, 2),
+    ]);
+    const feeds: Feed[] = [];
+    for (let i = 1; i <= 2; i++) {
+      feeds.push(FeedFixture.createFeedFixture(blog, {}, i));
+    }
+    await Promise.all([feedRepository.save(feeds), app.listen(7000)]);
+  });
+
+  it('최초 연결이 되면 트랜드 데이터를 최대 4개 받을 수 있다.', async () => {
+    // given
+    const es = new EventSource('http://localhost:7000/api/feed/trend/sse');
+    const timeout = new Promise((_, reject) =>
+      setTimeout(
+        () => reject(new Error('Timeout occurred before receiving data')),
+        1000,
+      ),
+    );
+    const eventResult = new Promise((resolve, reject) => {
+      es.onmessage = (event) => {
+        try {
+          const response = JSON.parse(event.data);
+          const data = response.data;
+          const idList = data.map((item) => item.id);
+          es.close();
+          resolve(idList);
+        } catch (error) {
+          es.close();
+          reject(error);
+        }
+      };
+      es.onerror = (error) => {
+        es.close();
+        reject(error);
+      };
+    });
+
+    // when
+    const idList = await Promise.race([eventResult, timeout]);
+
+    // then
+    expect(idList).toStrictEqual([1, 2]);
+  });
+
+  it('서버로부터 데이터를 받을 때, 게시글이 지워진 상황이라면 게시글을 받지 않는다.', async () => {
+    // given
+    await feedRepository.delete({ id: 2 });
+    const es = new EventSource('http://localhost:7000/api/feed/trend/sse');
+    const timeout = new Promise((_, reject) =>
+      setTimeout(
+        () => reject(new Error('Timeout occurred before receiving data')),
+        1000,
+      ),
+    );
+    const eventResult = new Promise((resolve, reject) => {
+      es.onmessage = (event) => {
+        try {
+          const response = JSON.parse(event.data);
+          const data = response.data;
+          const idList = data.map((item) => item.id);
+          es.close();
+          resolve(idList);
+        } catch (error) {
+          es.close();
+          reject(error);
+        }
+      };
+      es.onerror = (error) => {
+        es.close();
+        reject(error);
+      };
+    });
+
+    // when
+    const idList = await Promise.race([eventResult, timeout]);
+
+    // then
+    expect(idList).toStrictEqual([1]);
+  });
+});