app.rb

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  gem "rails", "7.0.0"
  gem "database_rewinder", "0.9.6"
  gem "rspec-rails", "5.0.2"

  #gem "mysql2", "0.5.3"
  #gem "ridgepole", "1.0.0"

  gem "sqlite3"
  gem "pry"
end

ENV['RAILS_ENV'] ||= 'test'

require "action_controller/railtie"
require "active_record"

module App
  class Engine < ::Rails::Engine
    isolate_namespace App
  end

  class UsersController < ActionController::Base
    def create
      User.create
    end

    def destroy
      User.first.destroy
    end
  end

  config = ActiveRecord::Base.configurations = { "test": { adapter: "sqlite3", database: ":memory:" } }
  ActiveRecord::Base.establish_connection(config["test"])

  ActiveRecord::Schema.define do
    create_table :users
  end

  class User < ActiveRecord::Base
  end
end

App::Engine.routes.draw do
  post "/users" => "users#create"
  delete "/users" => "users#destroy"
end

Rails.application.routes.draw do
  mount App::Engine, at: "/test"
end

require "rspec/rails"
require "rspec/autorun"
require "database_rewinder/railtie"
require "database_rewinder/cleaner"

module App
  RSpec.configure do |config|
    config.before(:suite) do
      DatabaseRewinder.init
      DatabaseRewinder.clean_all
    end

    config.after(:each) do
      DatabaseRewinder.clean
    end
  end

  RSpec.describe "RequestUser", type: :request do
    describe "POST #create" do
      it "should create record" do
        post "/users"
        expect(User.count).to eql 1
      end
    end

    describe "POST #create" do
      it "should destroy record" do
        delete "/users"
        expect(User.count).to eql 0
      end
    end
  end
end