Setting Up A Rails 5 Application With Postgres & RSpec

A basic cheat sheet for a Rails 5 project at Turing School.

Written by Anthony Ongaro, on 2023-01-23

Spin Up A New Rails Project

Begin in terminal

rails new application_name -T -d="postgresql" --skip-spring --skip-turbolinks

Command breakdown:

• -T remove standard testing (add RSpec later)
• -d="postgresql" use PostgreSQL for database (SQLite3 by default)
• --skip-spring & --skip-turbolinks skip things we don’t need at this scale

Ruby Gems

Add Gems

Add gems to :development :test group in Gemfile

group :development, :test do
  gem 'pry' # binding.pry
  gem 'rspec-rails'
  gem 'capybara' # feature tests
  gem 'launchy' # save_and_open_page
  gem 'faker' # use with factory_bot to generate fake data for tests
  gem 'factory_bot_rails'
  gem 'simplecov' # requires add'l setup
  gem 'shoulda-matchers' # requires add'l setup
  gem 'orderly' # tests order of appearance on webpage
end

Bundle Install Run bundle to install the gems from Gemfile

Gem Setup

Install RSpec:

rails generate rspec:install

In .gitignore: Add /coverage/ directory to bottom of file to ignore SimpleCov

In rails_helper.rb: Add code to top of file for SimpleCov

require 'simplecov'
SimpleCov.start

Add this code to bottom of file for Shoulda-Matcher (association testing)

Shoulda::Matchers.configure do |config|
  config.integrate do |with|
    with.test_framework :rspec
    with.library :rails
  end
end

Connect To GitHub Repo

Create New GitHub Repository, Add Remote Repo As Origin

git remote add origin git@github.com:<user_name>/<repo_name>.git

Create Local Initial Commit, Push To Origin

git push -u origin main

Probably create a new branch and then…

Initial Build-Out

Create

Build the PostgreSQL test and development databases for the project:

rails db:create

Create Database Migrations

Use dbdesigner to design initial schema before next steps. If you already have a schema.rb in place, dbdiagram is amazing. It lets you import directly from a copy and pasted schema.

Generate migrations for each initial table in database with columns and data types Table names are always plural

rails generate migration CreateSongs title:string length:integer play_count:integer
rails generate migration CreateArtists name:string age:integer :integer

• You do not need id, foreign_id, updated_at or created_at yet…

( You’ll want to investiate using rails generate model Songs... later. )

Add Timestamps To Migration Files in /db/migrate

Add t.timestamps to your new migration files in db directory (adds created_at/updated_at) Edit any mistakes you made with your terminal commands here before migrating.

class CreateInstruments < ActiveRecord::Migration[5.2]
  def change
    create_table :instruments do |t|
      t.string :brand
      t.string :type
      t.boolean :used
      t.boolean :needs_repair
      t.integer :price
      
      t.timestamps
    end
  end
end

Migrate Database with Current Migrations

Once done creating all migration files

rails db:migrate

Create Database Relationships

You can do this before or after the previous step, or any time in the future Create your database relationships to generate foreign_ids for ‘child’ tables

rails generate migration AddArtistToSongs store:references

Note: the singular parent class being added to the plural child class

An Artist has_many Songs, this is how you add a foreign id to Songs to identify its artist_id

Check Migration File

Make sure everything is correct, and then migrate changes into db. rails db:migrate

Create Many-To-Many Relationships

Once you have your initial tables set up, then you can migrate the relationships.

rails g migration CreateSnackMachines snack:references machine:references

This creates snack and machine relationship, with snack id + machine id

Check Schema

Verify schema.rb is all correct at this point or continue setting up tables and relationships as needed.

Seed the Database

Seed database with db/seeds.rb or go into rails console and start adding stuff

Start Building Model Tests

Start building tests, start model validations and relationships. These are just examples of different relationships tests and validations.

require 'rails_helper'

RSpec.describe User, type: :model, do
  describe 'relationships' do
    it { should belong_to :movies }
    it { should have_many :user_parties }
    it { should have_many(:parties).through(:user_parties) }
  end

  describe 'validations' do
    it { should validate_presence_of :name }
    it { should validate_presence_of :email }
    it { should validate_uniqueness_of :email }
  end
end

Quick Commands

# Start rails development server:
rails s rails server

# Start rails sql console
rails dbconsole

# Rails console to interact with objects/db:
rails c / `rails console`

# Drop, create, migrate database (!!: This Destroys Development DB)
rails db:{drop,create,migrate,seed}

# Seed from db/seeds.rb
rails db:seed

# Check project's routes in terminal (important)
rails routes

# Build models
rails generate model Task user:references name:string frequency:integer

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