http: add integration tests

[josephjclark]

We should add a suite of integration tests in the new http adaptor.

This creates a server and uses the http functions to call it.

As well as some very basic get/put/post stuff, it can test redirects, form data, auth and tls security - stuff that's harder to unit test with the undici mocks

--

Here's a unit test for http which uses redirects:

 it('can follow redirects', async () => {
    // mock intercept paths
    // note that the mock undici client won't respect the redirect
    testServer
      .intercept({
        path: '/api/fake-endpoint',
        method: 'GET',
      })
      .reply(
        301,
        1,
        {
          headers: {
            Location: 'https://www.example.com/api/fake-endpoint-2',
          },
        }
      );

    testServer
      .intercept({
        path: '/api/fake-endpoint-2',
        method: 'GET',
      })
      .reply(302, 2, {
        headers: {
          Location: 'https://www.example.com/api/fake-endpoint-3',
        },
      });

    testServer.intercept(
      {
        path: '/api/fake-endpoint-3',
        method: 'GET',
      }).reply(200, res => res.path)
    );

    const state = {
      configuration: {},
      data: {},
    };

    const finalState = await execute(
      get('https://www.example.com/api/fake-endpoint', {
        followAllRedirects: true,
      })
    )(state);

    expect(finalState.data.url).to.eql('/api/fake-endpoint-3');
  });

This test doesn't work against the undici mock interceptor because the redirect flag is not respected.

To get this test to pass, we should:

• create a lightweight http server in test
• add redirect routes to the server
• call the actual server
• test the result
• tear down the server

It's kind of a big test and not worth the time right now.

Here's a koa server we can use:

import Koa from "koa";

const server = new Koa();

server.use(async (ctx) => {
  if (ctx.url === "/redirect") {
    ctx.response.status = 301;
    ctx.response.set({ Location: "http://localhost:2222/foo" });
  } else {
    ctx.response.status = 200;
    ctx.response.body = "ok";
  }
});

server.listen(2222);