08 — Integration tests

Hub › JavaScript › Advanced › 08 Integration tests

Goal: write integration tests with Jest and supertest that exercise the full API against a test database.

Install dev dependencies

npm install -D jest supertest

Update package.json

Add to package.json:

{
  "scripts": {
    "test": "node --experimental-vm-modules node_modules/.bin/jest --forceExit --detectOpenHandles"
  }
}

Test setup

Create tests/helpers.js:

const { Pool } = require("pg");

const testPool = new Pool({
  host: process.env.PGHOST || "localhost",
  port: Number(process.env.PGPORT) || 5432,
  user: process.env.PGUSER || "postgres",
  password: process.env.PGPASSWORD || "postgres",
  database: process.env.PGDATABASE || "todos_test",
});

async function cleanDb() {
  await testPool.query("DELETE FROM todos");
  await testPool.query("DELETE FROM users");
}

module.exports = { testPool, cleanDb };

Override the db module in tests by setting PGDATABASE=todos_test.

Create test database

createdb todos_test
node bin/migrate.js
# (ensure PGDATABASE=todos_test is set)

Auth tests

Create tests/auth.test.js:

const request = require("supertest");
const app = require("../app");
const { cleanDb } = require("./helpers");

beforeEach(cleanDb);

describe("POST /api/auth/signup", () => {
  it("creates a user and returns a token", async () => {
    const res = await request(app)
      .post("/api/auth/signup")
      .send({ email: "test@test.com", password: "secret" });
    expect(res.status).toBe(201);
    expect(res.body.token).toBeDefined();
    expect(res.body.user.email).toBe("test@test.com");
  });

  it("rejects duplicate email", async () => {
    await request(app)
      .post("/api/auth/signup")
      .send({ email: "dup@test.com", password: "secret" });
    const res = await request(app)
      .post("/api/auth/signup")
      .send({ email: "dup@test.com", password: "secret" });
    expect(res.status).toBe(409);
  });
});

Todo tests

Create tests/todos.test.js:

const request = require("supertest");
const app = require("../app");
const { cleanDb } = require("./helpers");

let token;

beforeEach(async () => {
  await cleanDb();
  const res = await request(app)
    .post("/api/auth/signup")
    .send({ email: "todo@test.com", password: "pass" });
  token = res.body.token;
});

describe("POST /api/todos", () => {
  it("creates a todo", async () => {
    const res = await request(app)
      .post("/api/todos")
      .set("Authorization", `Bearer ${token}`)
      .send({ text: "test todo" });
    expect(res.status).toBe(201);
    expect(res.body.text).toBe("test todo");
    expect(res.body.done).toBe(false);
  });

  it("rejects when not authenticated", async () => {
    const res = await request(app)
      .post("/api/todos")
      .send({ text: "test" });
    expect(res.status).toBe(401);
  });
});

describe("GET /api/todos", () => {
  it("returns empty list initially", async () => {
    const res = await request(app)
      .get("/api/todos")
      .set("Authorization", `Bearer ${token}`);
    expect(res.status).toBe(200);
    expect(res.body).toEqual([]);
  });
});

Run tests

PGDATABASE=todos_test npm test

Expected output:

 PASS  tests/auth.test.js
 PASS  tests/todos.test.js

Tests:       6 passed, 6 total

Checkpoint

PGDATABASE=todos_test npm test 2>&1 | tail -5
# Tests:       6 passed, 6 total

---

Next: 09 GitHub Actions