Gist created for Rspec Article. Published first in medium.

RSPEC_ARTICLE_calculator_spec.rb

require('./calculator.rb')

context "Calculator" do 
  
  let(:calc){Calculator.new()} 

  describe "Addition" do 

    it "5 + 4 = 9" do
      expect(
        calc.addition(4,5)
      ).to be(9)         
    end

    it "5 + 4 != 10" do
      expect(
        calc.addition(4,5)
      ).not_to be(10) 
    end

  end  

  describe "Substraction" do

    it "7 - 4" do
      expect(
        calc.substraction(7,4)
      ).to be(3) 
    end

    it "8 - 4" do
      expect(
        calc.substraction(8,4)
      ).not_to be(5) 
    end
    
  end

  describe "Multiplication" do

    it "3 * 5" do
      expect(
        calc.multiplication(3,5)
      ).to be(15)
    end
    
    it "3 * 5" do
      expect(
        calc.multiplication(3,5)
      ).not_to be(24)
    end

  end

  describe "Division" do

    it "6 / 3" do
      expect(
        calc.division(6,3)
      ).to be(2.0)
    end

    it "6 / 3" do
      expect(
        calc.division(6,3)
      ).not_to be(55)
    end

    it "7 / 2" do
      expect(
        calc.division(7,2)
      ).to be(3.5)
    end

    it "1 / 0", :focus do
      expect(
        calc.division(1,0)
      ).to eq('Positive Infinity')
    end

    it "0 / 0" do
      expect(
        calc.division(0,0)
      ).to eq('Indeterminate')
    end
    
    it "-1 / 0" do
      expect(
        calc.division(-1,0)
      ).to eq('Negative Infinity')
    end

  end
end