cloner.rb

class Cloner
  def clone_array_of_hashes(a)
    a.map{|h| h.clone}
  end
end

cloner_spec.rb

require_relative "./cloner"

describe Cloner do
  let(:cloner) {Cloner.new}
  let(:orig_ah) { [{a: "A"},{b: "B"}] }
  let(:cloned_ah) { cloner.clone_array_of_hashes(orig_ah) }

  it "passes" do
    cloned_ah[0] #this is the only difference between the two tests
    orig_ah[0][:a] = "AA"
    expect(orig_ah[0]).to_not eq(cloned_ah[0])
  end

  it "fails but should pass" do
    orig_ah[0][:a] = "AA"
    expect(orig_ah[0]).to_not eq(cloned_ah[0])
  end
end