context.js

'use strict';

const setupRequests = require('../helpers/setup-requests.js');
const assert = require('assert');
const Koa = require('../..');

describe('app.context', () => {
  const app1 = new Koa();
  app1.context.msg = 'hello';
  const app2 = new Koa();

  it('should merge properties', async () => {
    app1.use((ctx, next) => {
      assert.equal(ctx.msg, 'hello');
      ctx.status = 204;
    });

    const request = setupRequests(app1);
    let res = await request('/');
    expect(res.status).toBe(204);
  });

  it('should not affect the original prototype', async () => {
    app2.use((ctx, next) => {
      assert.equal(ctx.msg, undefined);
      ctx.status = 204;
    });

    const request = setupRequests(app2);
    let res = await request('/');
    expect(res.status).toBe(204);
  });
});

setup-requests.js

'use strict';

const path = require('path');
const fetch = require('node-fetch');

module.exports = (koa) => {
  let urlBase = new Promise((resolve, reject) => {
    const server = koa.listen(0, () => {
      resolve('127.0.0.1:' + server.address().port);
    });
  });
  return async (url, options) => {
    url = 'http://' + path.join(await urlBase, url);
    return fetch(url, options);
  };
};