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: