test-unit-activesupport doesn't support parallelize yet

[hiroyuki-sato]

Rails6 introduced parallel methods

rails new command generates the following contents in test/test_helper.rb

class ActiveSupport::TestCase
  # Run tests in parallel with specified workers
  parallelize(workers: :number_of_processors)

  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
  fixtures :all

  # Add more helper methods to be used by all tests here...
end

After test-unit setting, I execute rails test command and I got the following error.

Traceback (most recent call last):
	53: from -e:1:in `<main>'
	52: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:72:in `require'
	51: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:72:in `require'
	50: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:59:in `load'
	49: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:59:in `load'
	48: from /private/tmp/test_unit_app/bin/rails:9:in `<main>'
	47: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/zeitwerk-2.4.1/lib/zeitwerk/kernel.rb:33:in `require'
	46: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
	45: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
	44: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	43: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
	42: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
	41: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/railties-6.0.3.4/lib/rails/commands.rb:18:in `<main>'
	40: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/railties-6.0.3.4/lib/rails/command.rb:46:in `invoke'
	39: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/railties-6.0.3.4/lib/rails/command/base.rb:69:in `perform'
	38: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/thor-1.0.1/lib/thor.rb:392:in `dispatch'
	37: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/thor-1.0.1/lib/thor/invocation.rb:127:in `invoke_command'
	36: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/thor-1.0.1/lib/thor/command.rb:27:in `run'
	35: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-rails-6.0.0/lib/rails/commands/test/test_command.rb:34:in `perform'
	34: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/autorunner.rb:66:in `run'
	33: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/autorunner.rb:434:in `run'
	32: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/autorunner.rb:106:in `block in <class:AutoRunner>'
	31: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:38:in `collect'
	30: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:131:in `add_load_path'
	29: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:43:in `block in collect'
	28: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:43:in `each'
	27: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:46:in `block (2 levels) in collect'
	26: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:90:in `collect_recursive'
	25: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:90:in `each'
	24: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:92:in `block in collect_recursive'
	23: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:90:in `collect_recursive'
	22: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:90:in `each'
	21: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:92:in `block in collect_recursive'
	20: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:85:in `collect_recursive'
	19: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:85:in `each'
	18: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:87:in `block in collect_recursive'
	17: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:112:in `collect_file'
	16: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:136:in `add_load_path'
	15: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/test-unit-3.3.6/lib/test/unit/collector/load.rb:114:in `block in collect_file'
	14: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/zeitwerk-2.4.1/lib/zeitwerk/kernel.rb:33:in `require'
	13: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
	12: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
	11: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	10: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
	 9: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
	 8: from /private/tmp/test_unit_app/test/channels/application_cable/connection_test.rb:1:in `<main>'
	 7: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/zeitwerk-2.4.1/lib/zeitwerk/kernel.rb:33:in `require'
	 6: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
	 5: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
	 4: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	 3: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
	 2: from /Users/user/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bootsnap-1.5.0/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
	 1: from /private/tmp/test_unit_app/test/test_helper.rb:8:in `<main>'
/private/tmp/test_unit_app/test/test_helper.rb:10:in `<class:TestCase>': undefined method `parallelize' for ActiveSupport::TestCase:Class (NoMethodError)

Workaround

comment(or remove) parallelize part

class ActiveSupport::TestCase
  # Run tests in parallel with specified workers
  #parallelize(workers: :number_of_processors) # <--- HERE

  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
  fixtures :all

  # Add more helper methods to be used by all tests here...
end

environment

• os: macOS 10.15.7
• ruby: 2.7.2p137
• rails: 6.0.3.4

[kou]

Wow. I didn't know it.

We need to add support for parallelization to test-unit.