Run RSpec tests on multiple processes at the same time

forking_rspec.rb

#!/usr/bin/env ruby

ENV['RAILS_ENV'] = 'test'
require 'benchmark'
rails_loading_time = Benchmark.measure { require './config/environment' }
puts "Rails env loaded in #{rails_loading_time}"

NUM_FORKS = 2
test_groups = `find ./spec -type f -iname "*foobar*"`.split("\n").in_groups(NUM_FORKS).to_a

pipes = {}

NUM_FORKS.times do |i|
  read_end, write_end = IO.pipe

  child_pid = fork do
    read_end.close

    $stdout.reopen(write_end)
    puts "[#{Process.pid}] Executing #{test_groups[i].join(' ')} ..."

    require 'rspec/autorun'
    test_groups[i].each {|f| require f }
  end

  write_end.close
  pipes[child_pid] = read_end
end

loop do
  break if pipes.length == 0

  readable, _, _ = IO.select(pipes.values)
  begin
    print readable.first.readchar
  rescue EOFError
    child_pid = pipes.find {|k, v| v == readable.first }.first
    pipes.delete(child_pid)
  end
end


status = Process.waitall
status.each do |s|
  puts "Process #{s.first} exited with #{s.last.exitstatus}"
end

non_zero = status.map(&:last).map(&:exitstatus).reject {|i| i == 0 }
if non_zero.empty?
  exit 0
else
  exit 1
end