Regression testing

 Regression testing

Regression testing is a type of testing that involves testing the software application after a change or modification has been made to ensure that existing functionality has not been affected. Here is an example of a regression test written in Ruby using the RSpec library:

perl

require 'calculator'

describe Calculator do

  describe '#add' do

    it 'returns the sum of two numbers' do

      calculator = Calculator.new

      expect(calculator.add(2, 3)).to eq(5)

    end

    

    it 'returns the sum of two negative numbers' do

      calculator = Calculator.new

      expect(calculator.add(-2, -3)).to eq(-5)

    end

  end

end

In this example, we define a class Calculator that contains a method add that performs addition operations. We also define a regression test that tests the add method of the Calculator class after a change has been made. The test ensures that the add method still returns the correct output after the change.