Validate uniqueness of Active Record attribute

Assuming, you have RSpec and Shoulda Matchers installed, you can add the following test:

# frozen_string_literal: true

require 'rails_helper'

RSpec.describe User, type: :model do
  describe 'validations' do
    subject { build(:user) }

    it { is_expected.to validate_presence_of(:email) }
    it { is_expected.to validate_uniqueness_of(:email).case_insensitive }
  end
end

To make test pass, you’d include the following in the User model:

# frozen_string_literal: true

class User < ApplicationRecord
  validates :email, presence: true, uniqueness: { case_sensitive: false }
end

Sources

• Official docs