Express · Lesson 10 of 15

Testing with Supertest

Hit your app with supertest, isolate the database and assert on status and body.

Intermediate
16 min read
3 objectives

Before this lessonLesson 9: Helmet, CORS and Rate Limits

What you will learn

Write a request test
Reset state between tests
Test an auth header

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Supertest calls your app without binding a port. Pair it with a test database or an in-memory fake.

A first test

import request from "supertest";
import { app } from "../src/app.js";

test("GET /health", async () => {
  const res = await request(app).get("/health");
  expect(res.status).toBe(200);
  expect(res.body).toEqual({ status: "ok" });
});

test("POST /tasks validates", async () => {
  const res = await request(app).post("/tasks").send({});
  expect(res.status).toBe(400);
});

Auth

test("GET /me needs a token", async () => {
  await request(app).get("/me").expect(401);
  const { body } = await request(app).post("/login").send({ email: "ada@example.com", password: "secret" });
  await request(app).get("/me").set("Authorization", `Bearer ${body.token}`).expect(200);
});

Export app without calling listen (do that in server.js). Reset tables in beforeEach or wrap tests in transactions.

Up next · Lesson 11Express with TypeScriptTyped Request handlers, a tsconfig that works for Node and extending Express types.