This gist demonstrates one way to write a Cucumber scenario that tests an asynchronous feature. It is essentially a two part test but it maintains the documentation value of a single, cohesive test.

async.feature

Feature: Testing an asynchronous thing

  @async @batch_1
  Scenario: Some big batch process
    Given some stuff is set up
    When the thing happens
    Then it worked

  @async @batch_2
  Scenario: Another big batch process
    Given some stuff is set up
    When a different thing happens
    Then it worked

cucumber.yml

async: -t @async

env.rb

require 'yaml'


# Somehow figure out if the external processes have occurred. Using a flag file as an example.
Before('@async') do |scenario|
  test_tags = scenario.source_tag_names
  relevant_flag = test_tags.select { |tag| tag =~ /batch/ }

  flags = File.open('flag_file.yml') { |file| YAML.load file }
  @thing_has_happened = flags[relevant_flag]
end


# This hook just toggles the flag in order to demonstrate both code paths. Presumably some 
# outside process would update the flag file once the triggered action is finished.
After('@async') do |scenario|
    test_tags = scenario.source_tag_names
    relevant_flag = test_tags.select { |tag| tag =~ /batch/ }

    flag_hash = File.open('flag_file.yml') { |file| YAML.load file }
    flag_hash[relevant_flag] = !@thing_has_happened

    File.write('flag_file.yml', flag_hash.to_yaml)
end

flag_file.yml

---
? - ! '@batch_1'
: false
? - ! '@batch_2'
: false

steps.rb

Given(/^some stuff is set up$/) do
  # Do whatever you need to set things up
end

When(/^the thing happens$/) do
  unless @thing_has_happened
    # Possibly trigger something


    # All done for now
    pending
  else
    # Possibly do some more stuff
  end
end

Then(/^it worked$/) do
  # Check for success
end

When(/^a different thing happens$/) do
  unless @thing_has_happened
    # Possibly trigger something


    # All done for now
    pending
  else
    # Possibly do some more stuff
  end
end