backtic_spec.rb

class BackTicks
  def run
    `pwd`
  end
end

describe BackTicks do
  subject { BackTicks.new }

  it "should execute run" do
    subject.should_receive(:`).with('pwd').and_return '/home'
    subject.run.should == '/home'
  end
end

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1 example, 0 failures

Very helpful, thanks!