Rspec/Rails and testing validates_uniquess_of with scope

Question

Here is my test code:

require 'spec_helper'

describe Classroom, focus: true do

  let(:user) { build_stubbed(:user) }

  describe "associations" do
    it { should belong_to(:user) }
  end

  describe "validations" do
    it { should validate_presence_of(:user) }
    it { should validate_uniqueness_of(:name).scoped_to(:user_id) }

    context "should create a unique classroom per user" do

      before(:each) do
        @class = build_stubbed(:classroom, name: "Hello World", user: user)
        @class2 = build_stubbed(:classroom, name: "Hello World", user: user)
      end

      it "should not create the second classroom" do
        @class2.should have(1).errors_on(:name)
      end
    end
  end

  describe "instance methods" do

    before(:each) do
      @classroom = build_stubbed(:classroom)
    end

    describe "archive!" do

      context "when a classroom is active" do
        it "should mark classroom as inactive" do
          @classroom.stub(:archive!)
          @classroom.active.eql? false
        end
      end

    end

  end

end

Here is my Classroom model:

class Classroom < ActiveRecord::Base
  attr_accessible :user, :name

  belongs_to :user

  validates :user, presence: true
  validates_uniqueness_of :name, scope: :user_id, message: "already exists"

  def archive!
    update_attribute(:active, false)
  end
end

When I run the tests, I receive the following errors:

1) Classroom validations 
     Failure/Error: it { should validate_uniqueness_of(:name).scoped_to(:user_id) }
       Expected errors to include "has already been taken" when name is set to "arbitrary_string", got errors: ["user can't be blank (nil)", "name already exists (\"arbitrary_string\")"]
     # ./spec/models/classroom_spec.rb:13:in `block (3 levels) in <top (required)>'

  2) Classroom validations should create a unique classroom per user should not create the second classroom
     Failure/Error: @classroom2.should have(1).errors_on(:name)
       expected 1 errors on :name, got 0
     # ./spec/models/classroom_spec.rb:24:in `block (4 levels) in <top (required)>'

I am fairly new to writing tests (especially with using Rspec). Just looking for someone to give me some advice on what I am doing wrong.

Answer 1

1. First validation failure :
   In your model, you have overridden the default message that rspec generates for uniqueness validation. So while testing such a validation, you have to use 'with_message' option of shoulda. So the test should be like
   "it { should validate_uniqueness_of(:name).scoped_to(:user_id) }.with_message('already exists')"

2. Second validation failure :
   When you write uniqueness validation spec yourself as in your second example, you have to create one record which is already present in database and build a second record with similar parameters. Then this duplicate record will not be valid and it will have errors as expected.
   So in before(:each) block, save the first @classroom record in database instead of just building it