Tutorial: How to install/setup RSpec (and Factory Girl) in Rails

This tutorial assumes that you have ruby, rails, and mysql installed on your machine. This tutorial also doesn’t explain much about RSpec or Factory Girl and will just show you a quick way to get them working in a RoR environment.

Create the Rails Project
Go to your projects directory and create a rails project. Just for fun, let’s call it ‘bank’:

Create MySQL Databases
Go into mysql and create the two databases that rails has set up the bank project to use:

Put Gems Into Environments
Edit the files

and

and add the following lines:

config.gem "thoughtbot-factory_girl", :lib => 'factory_girl', :source => 'http://gems.github.com'
config.gem "rspec", :version => '1.2.2', :lib => 'spec'
config.gem "rspec-rails", :version => '1.2.2', :lib => false

This sets up the test and development environments to use rspec and factory girl.

Install the Gems
Install the gems referenced in your environments:

You’ll see output that says that the gems were installed, if you didn’t have them already.

Bootstrap RSpec
Do a:

You will see the following:

This generates some default rspec files and directories that the project will use.

Generate Model, Test, and Migration with rspec_model
Do a:

You will see the following output:

This will create a default test at

and a BankAccount model in

and a migration in

You can also do a script/generate rspec_scaffold BankAccount.

Edit the Test
Go to

and you will see:

require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
 
describe BankAccount do
  before(:each) do
    @valid_attributes = {
    }
  end
 
  it "should create a new instance given valid attributes" do
    BankAccount.create!(@valid_attributes)
  end
end

Since this is a bank account, one of the behaviors that we would expect is to be able to make deposits into it. That being the case, let’s change the test to

require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
 
describe BankAccount do
  before(:each) do
    @bank_account = BankAccount.create
    @bank_account.balance = 0
  end
 
  it "should increase the balance upon deposit" do
    @bank_account.deposit(100)
    @bank_account.balance.should == 100
  end
end

Also, edit

and change ‘progress’ to ‘specdoc’ (because it will make rspec output look a lot better)

Edit the Migration
We need to add the ‘balance’ attribute to the model. Go to

(or some file like that)

and change the migration to

class CreateBankAccounts < ActiveRecord::Migration
  def self.up
    create_table :bank_accounts do |t|
      t.float :balance
 
      t.timestamps
    end
  end
 
  def self.down
    drop_table :bank_accounts
  end
end

Edit the Model Now we need to add the deposit method to the BankAccount model. Go to

Change the class to

class BankAccount < ActiveRecord::Base
 
  def deposit(amount)
    self.balance = self.balance + amount
  end
 
end

Migrate the DB, Run RSpec Now, do a

and then a

You should see:

At this point, RSpec is functioning.

Add Factory Girl
Want to add Factory Girl? The environments are already set up and gem is installed. The rest is not hard:

Create a ‘factories’ directory under the ‘spec’ directory.

and make the file

and put this inside:

Factory.define :bank_account do |ba|
  ba.add_attribute :balance, 0
end

Edit the Test
Open

Change the body of the before each block to

@bank_account = Factory(:bank_account, :balance => 0)

Since the factory you just made (spec/factories/bank_accounts.rb) automatically sets the balance to 0, you could leave the body with just

@bank_account = Factory(:bank_account)

and it would still work.

The finished spec/models/bank_account_spec.rb will look like this:

require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
 
describe BankAccount do
  before(:each) do
    @bank_account = Factory(:bank_account, :balance => 0)
  end
 
  it "should increase the balance upon deposit" do
    @bank_account.deposit(100)
    @bank_account.balance.should == 100
  end
end

Watch RSpec Run With Factory Girl
Watch the test run with Factory Girl:

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