Created simple Rails Rspec testing

user_spec.rb

require "rails_helper"

RSpec.describe User, :type => :model do

  before(:each) do
    @user = User.create!(first_name: "Astm", last_name: "Ali")
  end

  # Creating validation
  describe "Creating" do
    it "We should have now new user created" do
      expect(User.all.count).to eq(1)
    end
  end

  # Require fields validation
  describe "Require validations" do
    it "first name must be require" do
      @user.first_name = nil
      expect(@user).to_not be_valid
    end

    it "last name must be require" do
      @user.last_name = nil
      expect(@user).to_not be_valid
    end

  end

  # Uniqueness fields validation
  describe "Uniqueness validations" do
    it "first name must be unique" do
      should validate_uniqueness_of(:first_name)
    end

    it "last name must be unique" do
      should validate_uniqueness_of(:last_name)
    end

  end
  
  # Length fields validation
  describe "Length validations" do
    it "first name must be less than 20 characters" do
      @user.first_name = "A" * 21
      expect(@user).to_not be_valid
    end
    
    it "last name must be less than 20 characters" do
      @user.last_name = "A" * 21
      expect(@user).to_not be_valid
    end
  end
  
  
end