Express Testing with SuperTest Cheat Sheet

Setup

1. Install SuperTest: npm install supertest --save-dev
2. Import SuperTest: const request = require("supertest");
3. Import Express: const express = require("express");
4. Create an Express app: const app = express();
5. Use the router you want to test: app.use("/", index);

Writing Tests

• Use the request function from SuperTest on your Express app.
• Pass the route you want to test.
• Use .expect() to assert the responses.

Example

test("index route works", done => {
  request(app)
    .get("/")
    .expect("Content-Type", /json/)
    .expect({ name: "frodo" })
    .expect(200, done);
});

Testing POST Routes

• Use .post() instead of .get().
• Use .type() to set the content type.
• Use .send() to send the request body.
• Use .then() to wait for the POST request to finish before making another request.

Example

test("testing route works", done => {
  request(app)
    .post("/test")
    .type("form")
    .send({ item: "hey" })
    .then(() => {
      request(app)
        .get("/test")
        .expect({ array: ["hey"] }, done);
    });
});

Additional Notes

• The done parameter is used to signal that the test is complete in the case of asynchronous operations.
• SuperTest allows you to pass done into the last .expect() and calls it for you.
• SuperTest pulls from another related project called SuperAgent. Any method that you can call in SuperAgent you can also call from SuperTest.
• Read through the SuperTest docs and SuperAgent docs for more details.