parallel_tests
Speedup Test::Unit + RSpec + Cucumber + Spinach by running parallel on multiple CPU cores.
ParallelTests splits tests into even groups (by number of lines or runtime) and runs each group in a single process with its own database.
Setup for Rails
RailsCasts episode #413 Fast Tests
Install
Gemfile
:
gem 'parallel_tests', group: [:development, :test]
config/database.yml
Add to ParallelTests uses 1 database per test-process.
Process number | 1 | 2 | 3 |
ENV['TEST_ENV_NUMBER'] | '' | '2' | '3' |
test:
database: yourproject_test<%= ENV['TEST_ENV_NUMBER'] %>
Create additional database(s)
rake parallel:create
Copy development schema (repeat after migrations)
rake parallel:prepare
Run migrations in additional database(s) (repeat after migrations)
rake parallel:migrate
Setup environment from scratch (create db and loads schema, useful for CI)
rake parallel:setup
Drop all test databases
rake parallel:drop
Run!
rake parallel:test # Test::Unit
rake parallel:spec # RSpec
rake parallel:features # Cucumber
rake parallel:features-spinach # Spinach
rake parallel:test[1] --> force 1 CPU --> 86 seconds
rake parallel:test --> got 2 CPUs? --> 47 seconds
rake parallel:test --> got 4 CPUs? --> 26 seconds
...
Test by pattern with Regex (e.g. use one integration server per subfolder / see if you broke any 'user'-related tests)
rake parallel:test[^test/unit] # every test file in test/unit folder
rake parallel:test[user] # run users_controller + user_helper + user tests
rake parallel:test['user|product'] # run user and product related tests
rake parallel:spec['spec\/(?!features)'] # run RSpec tests except the tests in spec/features
Example output
2 processes for 210 specs, ~ 105 specs per process
... test output ...
843 examples, 0 failures, 1 pending
Took 29.925333 seconds
Run an arbitrary task in parallel
RAILS_ENV=test parallel_test -e "rake my:custom:task"
# or
rake parallel:rake[my:custom:task]
# limited parallelism
rake parallel:rake[my:custom:task,2]
Running things once
require "parallel_tests"
# preparation:
# affected by race-condition: first process may boot slower than the second
# either sleep a bit or use a lock for example File.lock
ParallelTests.first_process? ? do_something : sleep(1)
# cleanup:
# last_process? does NOT mean last finished process, just last started
ParallelTests.last_process? ? do_something : sleep(1)
at_exit do
if ParallelTests.first_process?
ParallelTests.wait_for_other_processes_to_finish
undo_something
end
end
Even test group run-times
Test groups are often not balanced and will run for different times, making everything wait for the slowest group. Use these loggers to record test runtime and then use the recorded runtime to balance test groups more evenly.
RSpec
Rspec: Add to your .rspec_parallel
(or .rspec
) :
--format progress
--format ParallelTests::RSpec::RuntimeLogger --out tmp/parallel_runtime_rspec.log
To use a custom logfile location (default: tmp/parallel_runtime_rspec.log
), use the CLI: parallel_test spec -t rspec --runtime-log my.log
Minitest
Add to your test_helper.rb
:
require 'parallel_tests/test/runtime_logger' if ENV['RECORD_RUNTIME']
results will be logged to tmp/parallel_runtime_test.log when RECORD_RUNTIME
is set,
so it is not always required or overwritten.
Loggers
RSpec: SummaryLogger
Log the test output without the different processes overwriting each other.
Add the following to your .rspec_parallel
(or .rspec
) :
--format progress
--format ParallelTests::RSpec::SummaryLogger --out tmp/spec_summary.log
RSpec: FailuresLogger
Produce pastable command-line snippets for each failed example. For example:
rspec /path/to/my_spec.rb:123 # should do something
Add to .rspec_parallel
or use as CLI flag:
--format progress
--format ParallelTests::RSpec::FailuresLogger --out tmp/failing_specs.log
(Not needed to retry failures, for that pass --only-failures to rspec)
Cucumber: FailuresLogger
Log failed cucumber scenarios to the specified file. The filename can be passed to cucumber, prefixed with '@' to rerun failures.
Usage:
cucumber --format ParallelTests::Cucumber::FailuresLogger --out tmp/cucumber_failures.log
Or add the formatter to the parallel:
profile of your cucumber.yml
:
parallel: --format progress --format ParallelTests::Cucumber::FailuresLogger --out tmp/cucumber_failures.log
Note if your cucumber.yml
default profile uses <%= std_opts %>
you may need to insert this as follows parallel: <%= std_opts %> --format progress...
To rerun failures:
cucumber @tmp/cucumber_failures.log
Setup for non-rails
gem install parallel_tests
# go to your project dir
parallel_test
parallel_rspec
parallel_cucumber
parallel_spinach
-
use
ENV['TEST_ENV_NUMBER']
inside your tests to select separate db/memcache/etc. (docker compose: expose it) -
Only run a subset of files / folders:
parallel_test test/bar test/baz/foo_text.rb
-
Pass test-options and files via
--
:parallel_rspec -- -t acceptance -f progress -- spec/foo_spec.rb spec/acceptance
-
Pass in test options, by using the -o flag (wrap everything in quotes):
parallel_cucumber -n 2 -o '-p foo_profile --tags @only_this_tag or @only_that_tag --format summary'
Options are:
-n [PROCESSES] How many processes to use, default: available CPUs
-p, --pattern [PATTERN] run tests matching this regex pattern
--exclude-pattern [PATTERN] exclude tests matching this regex pattern
--group-by [TYPE] group tests by:
found - order of finding files
steps - number of cucumber/spinach steps
scenarios - individual cucumber scenarios
filesize - by size of the file
runtime - info from runtime log
default - runtime when runtime log is filled otherwise filesize
-m, --multiply-processes [FLOAT] use given number as a multiplier of processes to run
-s, --single [PATTERN] Run all matching files in the same process
-i, --isolate Do not run any other tests in the group used by --single(-s)
--isolate-n [PROCESSES] Use 'isolate' singles with number of processes, default: 1.
--highest-exit-status Exit with the highest exit status provided by test run(s)
--specify-groups [SPECS] Use 'specify-groups' if you want to specify multiple specs running in multiple
processes in a specific formation. Commas indicate specs in the same process,
pipes indicate specs in a new process. Cannot use with --single, --isolate, or
--isolate-n. Ex.
$ parallel_tests -n 3 . --specify-groups '1_spec.rb,2_spec.rb|3_spec.rb'
Process 1 will contain 1_spec.rb and 2_spec.rb
Process 2 will contain 3_spec.rb
Process 3 will contain all other specs
--only-group INT[,INT]
-e, --exec [COMMAND] execute this code parallel and with ENV['TEST_ENV_NUMBER']
-o, --test-options '[OPTIONS]' execute test commands with those options
-t, --type [TYPE] test(default) / rspec / cucumber / spinach
--suffix [PATTERN] override built in test file pattern (should match suffix):
'_spec.rb$' - matches rspec files
'_(test|spec).rb$' - matches test or spec files
--serialize-stdout Serialize stdout output, nothing will be written until everything is done
--prefix-output-with-test-env-number
Prefixes test env number to the output when not using --serialize-stdout
--combine-stderr Combine stderr into stdout, useful in conjunction with --serialize-stdout
--non-parallel execute same commands but do not in parallel, needs --exec
--no-symlinks Do not traverse symbolic links to find test files
--ignore-tags [PATTERN] When counting steps ignore scenarios with tags that match this pattern
--nice execute test commands with low priority.
--runtime-log [PATH] Location of previously recorded test runtimes
--allowed-missing [INT] Allowed percentage of missing runtimes (default = 50)
--unknown-runtime [FLOAT] Use given number as unknown runtime (otherwise use average time)
--first-is-1 Use "1" as TEST_ENV_NUMBER to not reuse the default test environment
--fail-fast Stop all groups when one group fails (best used with --test-options '--fail-fast' if supported
--verbose Print debug output
--verbose-process-command Displays only the command that will be executed by each process
--verbose-rerun-command When there are failures, displays the command executed by each process that failed
--quiet Print only tests output
-v, --version Show Version
-h, --help Show this.
You can run any kind of code in parallel with -e / --exec
parallel_test -n 5 -e 'ruby -e "puts %[hello from process #{ENV[:TEST_ENV_NUMBER.to_s].inspect}]"'
hello from process "2"
hello from process ""
hello from process "3"
hello from process "5"
hello from process "4"
1 Process | 2 Processes | 4 Processes | |
RSpec spec-suite | 18s | 14s | 10s |
Rails-ActionPack | 88s | 53s | 44s |
TIPS
RSpec
- Add a
.rspec_parallel
to use different options, e.g. no --drb - Remove
--loadby
from.rspec
- Instantly see failures (instead of just a red F) with rspec-instafail
- Use rspec-retry (not rspec-rerun) to rerun failed tests.
- JUnit formatter configuration
- Use parallel_split_test to run multiple scenarios in a single spec file, concurrently. (
parallel_tests
works at the file-level and intends to stay that way)
Cucumber
- Add a
parallel: foo
profile to yourconfig/cucumber.yml
and it will be used to run parallel tests - ReportBuilder can help with combining parallel test results
- Supports Cucumber 2.0+ and is actively maintained
- Combines many JSON files into a single file
- Builds a HTML report from JSON with support for debug msgs & embedded Base64 images.
General
- [ZSH] use quotes to use rake arguments
rake "parallel:prepare[3]"
- [Memcached] use different namespaces
e.g.config.cache_store = ..., namespace: "test_#{ENV['TEST_ENV_NUMBER']}"
- Debug errors that only happen with multiple files using
--verbose
and cleanser export PARALLEL_TEST_PROCESSORS=13
to override default processor count- Shell alias:
alias prspec='parallel_rspec -m 2 --'
- [Spring] Add the spring-commands-parallel-tests gem to your
Gemfile
to getparallel_tests
working with Spring. --first-is-1
will make the first environment be1
, so you can test while running your full suite.
export PARALLEL_TEST_FIRST_IS_1=true
will provide the same result- email_spec and/or action_mailer_cache_delivery
- zeus-parallel_tests
- Distributed Parallel Tests on CI systems) learn how
parallel_tests
can run on distributed servers such as Travis and GitLab-CI. Also shows you how to use parallel_tests without addingTEST_ENV_NUMBER
-backends - Capybara setup
- Sphinx setup
- Capistrano setup let your tests run on a big box instead of your laptop
Contribute your own gotchas to the Wiki or even better open a PR :)
Authors
inspired by pivotal labs
Contributors
- Charles Finkel
- Indrek Juhkam
- Jason Morrison
- jinzhu
- Joakim Kolsjö
- Kevin Scaldeferri
- Kpumuk
- Maksim Horbul
- Pivotal Labs
- Rohan Deshpande
- Tchandy
- Terence Lee
- Will Bryant
- Fred Wu
- xxx
- Levent Ali
- Michael Kintzer
- nathansobo
- Joe Yates
- asmega
- Doug Barth
- Geoffrey Hichborn
- Trae Robrock
- Lawrence Wang
- Sean Walbran
- Lawrence Wang
- Potapov Sergey
- Łukasz Tackowiak
- Pedro Carriço
- Pablo Manrubia Díez
- Slawomir Smiechura
- Georg Friedrich
- R. Tyler Croy
- Ulrich Berkmüller
- Grzegorz Derebecki
- Florian Motlik
- Artem Kuzko
- Zeke Fast
- Joseph Shraibman
- David Davis
- Ari Pollak
- Aaron Jensen
- Artur Roszczyk
- Caleb Tomlinson
- Jawwad Ahmad
- Iain Beeston
- Alejandro Pulver
- Felix Clack
- Izaak Alpert
- Micah Geisel
- Exoth
- sidfarkus
- Colin Harris
- Wataru MIYAGUNI
- Brandon Turner
- Matt Hodgson
- bicarbon8
- seichner
- Matt Southerden
- Stanislaw Wozniak
- Dmitry Polushkin
- Samer Masry
- Volodymyr Mykhailyk
- Mike Mueller
- Aaron Jensen
- Ed Slocomb
- Cezary Baginski
- Marius Ioana
- Lukas Oberhuber
- Ryan Zhang
- Rhett Sutphin
- Doc Ritezel
- Alexandre Wilhelm
- Jerry
- Aleksei Gusev
- Scott Olsen
- Andrei Botalov
- Zachary Attas
- David Rodríguez
- Justin Doody
- Sandeep Singh
- Calaway
- alboyadjian
- Nathan Broadbent
- Vikram B Kumar
- Joshua Pinter
- Zach Dennis
- Jon Dufresne
- Eric Kessler
Michael Grosser
michael@grosser.it
License: MIT