Support for path params

[Cory O'Daniel]

It would be nice to have "path_params" that were a part of the request, that would be interpolated before the request was fired, instead of having to do it manually in the test.

Currently:

  test "[GET] /pets/{id} (200)" do
    pet = %Pet{name: "Chauncy", type: "cat"} |> Repo.insert!

    transaction = @swagger
      |> Apocryphal.Transaction.get("/pets/{id}", 200, @mime)

    path = Regex.replace(~r/{id}/, transaction.request.uri, "#{pet.id}")

    transaction
      |> put_in([:request, :uri], path)
      |> assert_schema
  end

Proposed:

  test "[GET] /pets/{id} (200)" do
    pet = %Pet{name: "Chauncy", type: "cat"} |> Repo.insert!

    @swagger
      |> Apocryphal.Transaction.get("/pets/{id}", 200, @mime)
      |> put_in([:request, :path_params], %{"id" => pet.id})
      |> assert_schema
  end