Response to http://niczsoft.com/2014/10/testing-rubys-initialize/

init_spec.rb

describe TestMe do
  describe '#initialize' do
    subject { test_me.value }

    context "default value" do
      let(:test_me) { TestMe.new }
      it { is_expected.to be_nil }
    end

    context "value passed as arg" do
      let(:test_me) { TestMe.new(3) }
      it { is_expected.to eq 3 }
    end
  end
end