global_state_example_spec.rb

describe do
  module Global
    class << self
      attr_accessor :shared_state
    end
  end

  shared_examples_for "example" do |value|
    puts "Defining state: #{Global.shared_state = value}"

    specify do
      puts "Using state #{Global.shared_state}"
      expect(Global.shared_state).to eq value
    end
  end

  it_should_behave_like "example", :my_value
  it_should_behave_like "example", :other_value
end

output.sh

Defining state: my_value
Defining state: other_value
Using state other_value
Using state other_value
F.

Failures:

  1) it should behave like example should eq :my_value
     Failure/Error: expect(Global.shared_state).to eq value

       expected: :my_value
            got: :other_value

       (compared using ==)

       Diff:
       @@ -1,2 +1,2 @@
       -:my_value
       +:other_value

     Shared Example Group: "example" called from ./examples_spec.rb:17
     # ./examples_spec.rb:13:in `block (3 levels) in <top (required)>'

Finished in 0.00108 seconds
2 examples, 1 failure

Failed examples:

rspec ./examples_spec.rb:11 # it should behave like example should eq :my_value