string_calculator_spec.rb

require File.join(File.dirname(__FILE__), 'string_calculator.rb')

describe StringCalculator do
  context "sum with an empty string" do
    it "returns zero" do
      subject.add("").should == 0
    end
  end

  context "sum with a string that contains one number" do
    io_expectations = {
      "1" => 1,
      "2" => 2,
      "3" => 3,
      "4" => 4,
      "5" => 5,
    }

    io_expectations.each do |input, output|
      it %{returns #{output} itself if input is #{input}} do
        subject.add(input).should == output
      end
    end
  end

  context "sum with a string that contains two numbers" do
    it "returns the sum of the two numbers" do
      subject.add("1,2").should == 3
    end
  end

  context "sum with a string that contains an arbitrary number of numbers" do
    it "returns the sum of the numbers" do
      subject.add("1,2,3").should == 6
    end
  end
  
  context "sum with a string that contains an arbitrary number of numbers separated with \\n or ," do
    it "returns the sum of the numbers" do
      subject.add("1,2,3\n4").should == 10
    end
  end

  context "support of a user defined delimiter for numbers" do
    it "returns the sum of the numbers" do
      subject.add("//;\n1;2;3\n4").should == 10
    end
  end

  context "called with negative numbers" do
    it "raise an exception \"negative not allowed [-2]\"" do
      expect { subject.add("//;\n1;2;3\n4;-2;5") }.to raise_error("negative not allowed [-2]")
    end

    it "raise an exception \"negative not allowed [-2, -10, -4, -7]\"" do
      expect { subject.add("//;\n1;2;3\n4;-2;5;-10;-4;3;-7") }.to raise_error("negative not allowed [-2, -10, -4, -7]")
    end
  end

  context "ignoring number greater than 1000" do
    it "returns 15 if sum [1,2,3,4,1000,1001,5]" do
      subject.add("//;\n1;2;3\n4;1000;1001;5").should == 15
    end
  end

  context "length of the delimiter has an arbitrary length" do
    it "returns the sum of the numbers" do
      subject.add("//[del]\n1del2del3\n4del1000del1001del5").should == 15
    end
  end

  context "number of defined delimiters is arbitrary" do
    it "returns the sum of the numbers" do
      subject.add("//[kill][them][all]\n1kill2them3\n4all1000kill1001them5").should == 15
    end
  end
end