swagger.rb

require 'rack/test'
require 'swagger/docs'

Minitest.after_run {
  puts Swagger.to_doc
}

module Swagger

  @apis = []

  def self.register(resource_listing)
    @resource_listing = resource_listing
  end

  def self.apis
    @apis
  end

  def self.to_doc
    rl = ResourceListing.new(@resource_listing[:api_version], @resource_listing[:info])
    rl.apis = @apis
    rl.to_doc
  end

  class ResourceListing
    attr_accessor :apis
    def initialize(api_version = '1.0', info = '')
      @swagger_version = '1.2'
      @apis            = []
      @api_version     = api_version
      @info            = info
      @authorizations  = []
    end

    def to_doc
      MultiJson.dump(
        swaggerVersion: @swagger_version,
        apis:           @apis.map(&:to_doc),
        apiVersion:     @api_version,
        info:           @info,
        authorizations: @authorizations
      )
    end
  end

  class Resource
    def initialize
      @operations = []
    end

    def add_operation(operation)
      @operations << Operation.new(operation)
    end

    def to_doc
      {
        path: "I'm an Api",
        operations: @operations.map(&:to_doc)
      }
    end
  end

  class Operation
    def initialize(operation)
      @operation = operation
    end

    def to_doc
      @operation.to_s
    end
  end

  class Test < Minitest::Test
    include Rack::Test::Methods

    module Assertions
      require 'json-schema'

      def assert_valid_json_schema(schema, json)
        assert JSON::Validator.validate(schema, json)
      end
    end

    include Assertions

    def self.inherited(klass)
      super
      klass.instance_variable_set(:@resource, Resource.new)
      Swagger.apis << klass
    end

    def self.resource
      @resource
    end

    def self.to_doc
      resource.to_doc
    end

    def swagger(operation, &block)
      block.call
      add_operation(operation)
    end

    def summary(str)

    end

    def notes(str)

    end

    def schema(json)
      open(File.expand_path("../schema/#{json}", __FILE__)).read
    end

    private

    def add_operation(operation)
      self.class.resource.add_operation(operation)
    end
  end
end

test_account_creation.rb

require 'test_helper'

class TestAccountCreation < Swagger::Test

  def test_basic_creation
    swagger(:create) do
      summary 'Create Account'
      notes 'This creates a new account'

      post '/account?partner=cox', MultiJson.dump(body)
      assert last_response.ok?
      assert_valid_json_schema schema('account.json'), last_response.body
    end
  end
end

test_helper.rb

Swagger.register(
  api_extension_type: :json,
  api_file_path:      'public/api/v1/',
  base_uri:           'http://api.somedomain.com',
  api_version:        '1.0',
  info:               ''
)