Add request assertion feature to server

[aquamme]

Implements #845

The server tracks all handled requests and provides an API to allow
users to check whether a request matching the given parameters has
been made since the server was started.

  server.received.get.to('/contacts', { name: 'Darth Vader' })
  server.didNotReceive.post.to('any');
  server.received.get.to(/\/secrets.*/);
  server.didNotReceive.request.to('/robot/5');
  server.received.put.with({ name: 'Jack' });

I ended up adding RegExp support mostly because it was simpler than adding support for paths like "/posts/:id".

There is also a getter for the last request made to the server:

  server.lastRequest

Comments and suggestions are welcome!

[aquamme]

Not sure if RequestAssertion is the best name since 'assertion' is a loaded term. Maybe something like RequestChecker?

[aquamme]

A few other things I'd like to do/consider/I missed:

• Add an option to cap the number of requests that the server holds on to
• Add support for comparing POST payloads with nested attribute Done
• Have the feature report the number of matching requests instead of a boolean -- might want to rework the DSL a bit if this idea is pursued -- server.received.post.to('/posts') doesn't look like it would return a number

[samselikoff]

Sorry about delay, hoping to get to this soon.

Just glancing over, will folks want to assert against content type or other things? Should we

assert.ok(this.server.received.post.to('/contacts', {
  with: {
    body: { name: 'Bilbo', age: 111 },
    headers: {
      'ContentType': 'foo'
    }
  })
);

Don't have to change right now, just a quick thought.

[aquamme]

I like the idea. I'm on vacation until the 4th, so I won't be able to update the PR until then. Glad to hear any other feedback you may have when you get to it. Thanks!

[samselikoff]

Few suggestions:

• Make _requests public: server.requests. This way folks can inspect during dev, or even use w/their assertions (assert.equal(server.requests.length, 3);)
• Move server.lastRequest to server.requests.last (I think you can define a property on the array)
• I think the DSL currently doesn't allow server.received.post, right? You have to specify a url? ... thinking about this, I think it's okay.
• Originally I said enable only in testing by default, but I think we should enable in all envs by default, and maybe add an option to disable if memory gets out of hand. (We can do this in a new PR).

[aquamme]

Great feedback -- I should have time to make those changes tomorrow evening.

[aquamme]

All right, this is ready for another peek.

server.received... returns the number of matching requests, while server.didNotReceive returns a boolean. So you can do things like

// Two GETs are made to '/contacts', then...
assert.equal(server.received.get.to('/contacts'), 2);
assert.ok(server.received.get.to('/contacts'));
assert.ok(server.didNotReceive.post.to('/contacts'));

You can assert against any FakeXHR attributes:

assert.ok(server.received.get.to('/contacts', { requestHeaders: { 'Foo': 'Bar' } }));

Also made requests a public property and added a last property.

I think the DSL currently doesn't allow server.received.post, right? You have to specify a url? ... thinking about this, I think it's okay.

I don't see how we could make that syntax work while still allowing further chaining with 'to'. That aside, I did have a mechanism for allowing any URLs but I removed it because I didn't like the API (server.received.request.to('any')), but it could easily be added back in some form.

[aquamme]

@samselikoff -- any further changes you'd like to see on this? I can write up some documentation once you give it the 👍

[samselikoff]

Closing this as stale, but keeping a reference to it in miragejs/miragejs#217 in case we want to reference these APIs.