Run minitest tests in batches

README.md

Usage

It requires two environment variables:

• TEST_WORKERS - Total number of workers or batches. It uses to identify a total number of batches, that would be run in parallel. Default: 1
• TEST_WORKER_NUM - Current worker id. The value is between 1 and TEST_WORKERS

$ bundle exec rake test:parallel TEST_WORKERS=5 TEST_WORKER_NUM=1

test.rake

namespace :test do
  desc "Parallel tests. Use TEST_WORKERS and TEST_WORKER_NUM. TEST_WORKER_NUM in range from 1..TEST_WORKERS"
  task :parallel do
    workers = ENV.fetch("TEST_WORKERS", 1).to_i
    worker = ENV.fetch("TEST_WORKER_NUM", 1).to_i
    buckets = Array.new(workers) { [] }

    # Fill the buckets
    i = 0
    files = Dir["test/*_test.rb"].entries.sort {|f| File.size(f) }
    files.each do |f|
      i = 0 if buckets.size == i
      buckets[i] << f
      i += 1
    end

    if worker < 1 || worker > workers
      fail "TEST_WORKER_NUM is not correct: #{worker}. Check that it greater or equal 1 and less or equal TEST_WORKERS: #{workers}"
    end

    files = buckets[worker-1].join(" ")
    args = "-Ilib:test -r 'rake/rake_test_loader.rb' #{files} -v #{ENV.fetch("TESTOPTS", "")}"
    ruby args do |ok, status|
      if !ok && status.respond_to?(:signaled?) && status.signaled?
        raise SignalException.new(status.termsig)
      elsif !ok
        status  = "Command failed with status (#{status.exitstatus})"
        details = ": [ruby #{args}]"
        message = status + details
        fail message
      end
    end
  end
end