How to make specs fail if they are too slow.

spec_helper.rb

RSpec.configure do |c|
  { unit: 0.1, integration: 0.5 }.each do |type, max_time|
    c.after(:each, example_group: { file_path: %r|spec/#{type}| }) do
      run_time = Time.now - example.metadata.fetch(:execution_result).fetch(:started_at)
      if run_time > max_time
        raise "Example took too long: #{run_time} seconds (max is #{max_time} seconds)."
      end
    end
  end
end

In response to https://twitter.com/joshuaclayton/status/253219624982814720:

I've played around with this a bit. In the example above, specs in spec/unit fail if they take longer than 0.1 seconds, and specs in spec/integration fail if they take longer than 0.5 seconds.

Problem is, I found the runtime of individual specs to be pretty inconsistent, presumably due to the random times GC kicks in. You'd probably have to control the GC so that it never runs during an example to make the times more consistent to use this approach, or make the times reallly lenient.