test.rb

require 'rspec'

describe "why freezing constants isn't cargo-culting" do

  describe "unfrozen constants" do
    THAWED_STRING = "Thawed"

    def bar
      THAWED_STRING
    end

    it "doesn't raise an error when I edit #bar" do
      expect { bar << ", silly developer" }.to_not raise_error
      bar.should == "Thawed, silly developer"
    end

  end

  describe "frozen constants" do
    FROZEN_STRING = "Frozen".freeze

    def bar
      FROZEN_STRING
    end

    it "throws an error when I edit #bar" do
      expect { Foo.new.bar << " silly developer"  }.to raise_error
    end
  end

end