Testing State Machine scopes

test.rb

describe "scopes" do

  # this doesn't work for state machine
  # it "has scope :repaid" do
  #   AccountTransaction.should respond_to(:repaid)
  #   AccountTransaction.repaid.where_values_hash.should == { :state => :repaid }
  # end
  
  # The easiest solution
  before(:all) do
    %i(new pending posted cancelled repaid failed).each { |state| FactoryGirl.create(:account_transaction, state: state) }
  end
  
  it "has scope repaid" do
    AccountTransaction.repaid.pluck(:state).should == %w(repaid)
  end
  
  it "has scope active" do
    AccountTransaction.active.pluck(:state).should == %w(new pending posted)
  end

  # Using where_clauses
  it "has scope repaid" do
    where = AccountTransaction.repaid.arel.where_clauses
    where.should include "(\"account_transactions\".\"state\" IN ('repaid'))"
  end

end

# Shared Example:

module ModelHelpers
  RSpec.shared_examples "scoped state machine" do |model, scope_name, states|
    let(:scoped) { model.send(scope_name).arel.where_clauses }
    let(:table) { model.to_s.underscore.pluralize.to_sym }

    it "has scope #{scope_name} with states [#{[states].flatten.join ' '}]" do
      scoped.should include "(\"#{table}\".\"state\" IN ('#{[states].flatten.join "','"}'))"
    end
  end
end

# usage: 

it_behaves_like "scoped state machine", AccountTransaction, :repaid, 'repaid'
it_behaves_like "scoped state machine", AccountTransaction, :active, %w(new pending posted)

# Not sure about `[states].flatten` 2 times, I'll be glad to any suggestions about this topic.