Cannot test async_sinatra with cucumber

[rtyler]

-> % bundle exec cucumber
Feature: Herp

  Scenario: Derp          # features/test.feature:3
    Given I am a bug      # features/step_definitions/derp_steps.rb:1
    When I get "/"        # features/step_definitions/derp_steps.rb:4
      undefined method `options' for #<Rack::Head:0x7f786dfbdf50> (NoMethodError)
      ./features/step_definitions/derp_steps.rb:5:in `/^I get "([^"]*)"$/'
      features/test.feature:5:in `When I get "/"'
    Then I should asplode # features/step_definitions/derp_steps.rb:9

Failing Scenarios:
cucumber features/test.feature:3 # Scenario: Derp

1 scenario (1 failed)
3 steps (1 failed, 1 skipped, 1 passed)
0m0.007s
-> %  

I've got a full reproduction test case in this GitHub repository

[rtyler]

Looks like this is fixed in this branch from @mcolyer

[raggi]

This is fixed in master, and will be included in the next release