Shoulda Matchers: how to test conditional validations

Shoulda Matchers Archive don't provide canditional validations (validations with if: option). Here is how to write tests for the condition:

Class:

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

Test:

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describe 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