Rails 3.1, RSpec: testing model validations

Question

I have started my journey with TDD in Rails and have run into a small issue regarding tests for model validations that I can\'t seem to find a solution to. Let\'s say I have a U

Answer 1

CONGRATULATIONS on you endeavor into TDD with ROR I promise once you get going you will not look back.

The simplest quick and dirty solution will be to generate a new valid model before each of your tests like this:

 before(:each) do
    @user = User.new
    @user.username = "a valid username"
 end

BUT what I suggest is you set up factories for all your models that will generate a valid model for you automatically and then you can muddle with individual attributes and see if your validation. I like to use FactoryGirl for this:

Basically once you get set up your test would look something like this:

it "should have valid factory" do
    FactoryGirl.build(:user).should be_valid
end

it "should require a username" do
    FactoryGirl.build(:user, :username => "").should_not be_valid
end

Oh ya and here is a good railscast that explains it all better than me:

good luck :)

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UPDATE: As of version 3.0 the syntax for factory girl has changed. I have amended my sample code to reflect this.