rspec match optional keyword arguments

# Code to be tested

class Calculator
  def add(a, b, multiplier: 1)
    (a + b) * multiplier
  end
end

# RSpec test

RSpec.describe Calculator do
  describe '#add' do
    context 'with mandatory arguments' do
      it 'returns the sum of two numbers' do
        calculator = Calculator.new
        result = calculator.add(3, 4)
        expect(result).to eq(7)
      end
    end

    context 'with optional multiplier' do
      it 'multiplies the sum by the multiplier' do
        calculator = Calculator.new
        result = calculator.add(3, 4, multiplier: 2)
        expect(result).to eq(14)
      end
    end
  end
end