collect the body and make assert against the collected body

we don't need an instance to figure out what type of response to
allocate.  Later we'll pull this up the stack and pass the response
object down

This saves a lambda and request allocation on each request.

controllers should always go through the `action` class method so that
their middleware is respected.

now the caller can just treat it like a regular controller even though
it will return a 404

They are already required in `actionpack/lib/action_dispatch.rb` (L25-L26)

This `protected` keyword looks like some leftover, since
we are not using explicit receiver, this should go under `private`

We don't want to directly access the env hash

I want to implement this with something besides `@env` in the future, so
lets stop directly referencing it.

superclass already has this method, so remove this one

the dispatcher class isn't configurable anymore, so pull up allocation
to the method that needs it.

Now that we don't have subclasses depending on this method (they augment
the request class instead of the dispatch class) we can remove this
method and directly ask the request object for the controller class

We should keep the route set generation logic in one place

we don't need it anymore.  We always use the same dispatcher in tests.

If we subclass and augment the superclass, then we don't need to have
setters for particular things on the superclass.

`💅`

controller class resolution has been moved to the request object, so we
should override that method instead of relying on the RouteSet to
generate the controller class.

we already have a request, so we should use the methods on the request
to access the path info information

Creates fewer request objects and helps to abstract away from internals

try to remove dependencies on `@env` so we can have more flexible
internals

May be missed in 5fe14163 commit
Also fixes the broken build