Shoulda Matchers: how to test conditional validations

Copyclass Employee < ActiveRecored::Base
  validates :office, presence: true, if: manager?
  
  def manager?
    ...
  end
end

Copydescribe Employee do

  describe '#office' do
    
    context 'is a manager' do
      before { allow(subject).to receive(:manager?).and_return(true) }
      it { is_expected.to validate_presence_of(:office) }
    end
    
    context 'is not a manager' do
      before { allow(subject).to receive(:manager?).and_return(false) }
      it { is_expected.not_to validate_presence_of(:office) }
    end
    
  end
end