How to test Polka's middleware with supertest

[motss]

Polka does not work well with supertest. Is there alternative yet simple way to test Polka's middleware or router handler in a similar fashion?

FYI, I'm using Polka + TypeScript + Jest.

healthcheck.js

module.exports = function healthcheck() {
  return (_, res) => res.end('OK');
};

healthcheck.spec.js

// With `supertest` in Express...

const express = require('express'); // const polka = require('polka');
const supertest = require('supertest');

const healthcheck = require('../healthcheck.js');

describe('test-route', () => {
  it('returns', async (done) => {
    try {
     const app = express()); // const app = polka();
     const rq = supertest(app.use('/healthcheck', healthcheck()); // throw error when using `polka`

     rq.get('/healthcheck')
        .expect(200)
        .end((err, res) => {
          if (err) throw err;
          
          expect(res).toStrictEqual('OK');
          done();
        });
    } catch (e) {
      throw e;
    }
  }, 10e3);

});

[lukeed]

Hey,

Think supertest is expecting the app handler directly. Try this:

let { handler } = polka().use('/health', health check());
supertest(handler);

[motss]

@lukeed Thank you so much for the solution. This works perfectly. Should this be included in the docs for future reference?

[lukeed]

Great, glad to hear it!

I'll make sure to add a clear note somewhere. Basically, anything that expects a express() will need to take polka().handler

I'll document this better in my next Polka push