aruba.rb

require 'aruba/cucumber'
require 'aruba/processes/in_process'
require 'rascal/cli'

# https://github.com/erikhuda/thor/wiki/Integrating-with-Aruba-In-Process-Runs
class InProcessCliRunner

  # Allow everything fun to be injected from the outside while defaulting to normal implementations.
  def initialize(argv, stdin = STDIN, stdout = STDOUT, stderr = STDERR, kernel = Kernel)
    @argv, @stdin, @stdout, @stderr, @kernel = argv, stdin, stdout, stderr, kernel
  end

  def execute!
    exit_code = begin
      # Thor accesses these streams directly rather than letting them be injected, so we replace them...
      $stderr = @stderr
      $stdin = @stdin
      $stdout = @stdout

      # Run our normal Thor app the way we know and love.
      previous_program_name = $PROGRAM_NAME
      $PROGRAM_NAME = 'rascal'
      Rascal::CLI::Main.start(@argv)

      # Thor::Base#start does not have a return value, assume success if no exception is raised.
      0
    rescue StandardError => e
      # The ruby interpreter would pipe this to STDERR and exit 1 in the case of an unhandled exception
      b = e.backtrace
      @stderr.puts("#{b.shift}: #{e.message} (#{e.class})")
      @stderr.puts(b.map{|s| "\tfrom #{s}"}.join("\n"))
      1
    rescue SystemExit => e
      e.status
    ensure
      # add additional cleanup code here

      $stderr = STDERR
      $stdin = STDIN
      $stdout = STDOUT
      $PROGRAM_NAME = previous_program_name
    end

    # Proxy our exit code back to the injected kernel.
    @kernel.exit(exit_code)
  end
end

Aruba.configure do |config|
  config.command_launcher = :in_process
  config.main_class = InProcessCliRunner
end

Before('@separate-process') do
  aruba.config.command_launcher = :spawn
end