example mocking with undici/native fetch

Author: HugoDF

package-lock.json

@@ -29,6 +29,7 @@
   "devDependencies": {
     "@biomejs/biome": "1.5.1",
     "esmock": "2.6.2",
-    "nock": "^13.4.0"
+    "nock": "^13.4.0",
+    "undici": "^6.3.0"
   }
 }

package.json

@@ -0,0 +1,80 @@
+// @ts-nocheck
+import { test, describe, before, after } from "node:test";
+import assert from "node:assert/strict";
+import request from "supertest";
+
+import { MockAgent, setGlobalDispatcher } from "undici";
+
+import express, { Router } from "express";
+
+const hugo = (router = new Router()) => {
+	router.get("/hugo", async (_request, res) => {
+		const userData = await fetch("https://api.github.com/users/HugoDF").then(
+			(res) => res.json(),
+		);
+
+		const { blog, location, bio, public_repos } = userData;
+		return res.json({
+			blog,
+			location,
+			bio,
+			publicRepos: public_repos,
+		});
+	});
+	return router;
+};
+
+const initHugo = () => {
+	const app = express();
+	app.use(hugo());
+	return app;
+};
+
+const mockAgent = new MockAgent();
+
+describe("GET /hugo", () => {
+	before(() => {
+		mockAgent.disableNetConnect();
+		mockAgent.enableNetConnect("127.0.0.1");
+		setGlobalDispatcher(mockAgent);
+	});
+
+	after(async () => {
+		await mockAgent.close();
+	});
+
+	test("It should fetch HugoDF from GitHub", async () => {
+		const ghMocks = mockAgent.get("https://api.github.com");
+		ghMocks.intercept({ path: "/users/HugoDF" }).reply(200, {
+			blog: "https://codewithhugo.com",
+			location: "London",
+			bio: "Developer, JavaScript",
+			public_repos: 39,
+		});
+
+		const app = initHugo();
+		await request(app).get("/hugo");
+
+		mockAgent.assertNoPendingInterceptors();
+		assert.deepEqual(mockAgent.pendingInterceptors(), []);
+	});
+	test("It should 200 and return a transformed version of GitHub response", async () => {
+		const ghMocks = mockAgent.get("https://api.github.com");
+		ghMocks.intercept({ path: "/users/HugoDF" }).reply(200, {
+			blog: "https://codewithhugo.com",
+			location: "London",
+			bio: "Developer, JavaScript",
+			public_repos: 39,
+		});
+
+		const app = initHugo();
+		const res = await request(app).get("/hugo");
+
+		assert.deepEqual(res.body, {
+			blog: "https://codewithhugo.com",
+			location: "London",
+			bio: "Developer, JavaScript",
+			publicRepos: 39,
+		});
+	});
+});

src/06.02-req-interception-native-fetch.test.js

@@ -8,7 +8,7 @@ import express, { Router } from "express";
 import axios from "axios";
 
 const hugo = (router = new Router()) => {
-	router.get("/hugo", async (request_, res) => {
+	router.get("/hugo", async (_request, res) => {
 		const { data: userData } = await axios.get(
 			"https://api.github.com/users/HugoDF",
 		);