# parallel_tests [![Gem Version](https://badge.fury.io/rb/parallel_tests.svg)](https://rubygems.org/gems/parallel_tests) [![Build status](https://github.com/grosser/parallel_tests/workflows/test/badge.svg)](https://github.com/grosser/parallel_tests/actions?query=workflow%3Atest) Speedup Minitest + RSpec + Turnip + Cucumber + Spinach by running parallel on multiple CPU cores.
ParallelTests splits tests into balanced groups (by number of lines or runtime) and runs each group in a process with its own database. Setup for Rails =============== [RailsCasts episode #413 Fast Tests](http://railscasts.com/episodes/413-fast-tests) ### Install `Gemfile`: ```ruby gem 'parallel_tests', group: [:development, :test] ``` ### Add to `config/database.yml` ParallelTests uses 1 database per test-process.
Process number123
ENV['TEST_ENV_NUMBER']'''2''3'
```yaml test: database: yourproject_test<%= ENV['TEST_ENV_NUMBER'] %> ``` ### Create additional database(s) rake parallel:create ### (Multi-DB) Create individual database rake parallel:create: rake parallel:create:secondary ### Copy development schema (repeat after migrations) rake parallel:prepare ### Run migrations in additional database(s) (repeat after migrations) rake parallel:migrate ### (Multi-DB) Run migrations in individual database 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 ### (Multi-DB) Drop individual test database rake parallel:drop: ### Run! rake parallel:test # Minitest 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 ```Bash 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 =================== ```Ruby 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 runtimes ======================== Test groups will often run for different times, making the full test run as slow as the slowest group. Step 1: Use these loggers (see below) to record test runtime Step 2: Your next run will use the recorded test runtimes (use `--runtime-log ` if you picked a location different from below) ### 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`: ```ruby 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. ### TODO: add instructions for other frameworks 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 pasteable command-line snippets for each failed example. For example: ```bash 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](https://relishapp.com/rspec/rspec-core/docs/command-line/only-failures) to rspec) RSpec: VerboseLogger ----------------------- Prints a single line for starting and finishing each example, to see what is currently running in each process. ``` # PID, parallel process number, spec status, example description [14403] [2] [STARTED] Foo foo [14402] [1] [STARTED] Bar bar [14402] [1] [PASSED] Bar bar ``` Add to `.rspec_parallel` or use as CLI flag: --format ParallelTests::RSpec::VerboseLogger 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] Only run the given group numbers. Note that this will force the 'filesize' grouping strategy (even when the runtime log is present) unless you explicitly set it otherwise via the '-group-by' flag. -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-command Displays the command that will be executed by each process and 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 Process2 Processes4 Processes
RSpec spec-suite18s14s10s
Rails-ActionPack88s53s44s
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](https://github.com/grosser/rspec-instafail) - Use [rspec-retry](https://github.com/NoRedInk/rspec-retry) (not rspec-rerun) to rerun failed tests. - [JUnit formatter configuration](https://github.com/grosser/parallel_tests/wiki#with-rspec_junit_formatter----by-jgarber) - Use [parallel_split_test](https://github.com/grosser/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](https://github.com/grosser/parallel_tests/issues/747#issuecomment-580216980)) ### Cucumber - Add a `parallel: foo` profile to your `config/cucumber.yml` and it will be used to run parallel tests - [ReportBuilder](https://github.com/rajatthareja/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](https://github.com/grosser/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](https://github.com/DocSpring/spring-commands-parallel-tests) gem to your `Gemfile` to get `parallel_tests` working with Spring. - `--first-is-1` will make the first environment be `1`, 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](https://github.com/grosser/parallel_tests/wiki) - [zeus-parallel_tests](https://github.com/sevos/zeus-parallel_tests) - [Distributed Parallel Tests on CI systems)](https://github.com/grosser/parallel_tests/wiki/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 adding `TEST_ENV_NUMBER`-backends - [Capybara setup](https://github.com/grosser/parallel_tests/wiki) - [Sphinx setup](https://github.com/grosser/parallel_tests/wiki) - [Capistrano setup](https://github.com/grosser/parallel_tests/wiki/Remotely-with-capistrano) let your tests run on a big box instead of your laptop Contribute your own gotchas to the [Wiki](https://github.com/grosser/parallel_tests/wiki) or even better open a PR :) Authors ==== inspired by [pivotal labs](https://blog.pivotal.io/labs/labs/parallelize-your-rspec-suite) ### [Contributors](https://github.com/grosser/parallel_tests/contributors) - [Charles Finkel](http://charlesfinkel.com/) - [Indrek Juhkam](http://urgas.eu) - [Jason Morrison](http://jayunit.net) - [jinzhu](http://github.com/jinzhu) - [Joakim Kolsjö](http://www.rubyblocks.se) - [Kevin Scaldeferri](http://kevin.scaldeferri.com/blog/) - [Kpumuk](http://kpumuk.info/) - [Maksim Horbul](http://github.com/mhorbul) - [Pivotal Labs](http://www.pivotallabs.com) - [Rohan Deshpande](http://github.com/rdeshpande) - [Tchandy](http://thiagopradi.net/) - [Terence Lee](http://hone.heroku.com/) - [Will Bryant](http://willbryant.net/) - [Fred Wu](http://fredwu.me) - [xxx](https://github.com/xxx) - [Levent Ali](http://purebreeze.com/) - [Michael Kintzer](https://github.com/rockrep) - [nathansobo](https://github.com/nathansobo) - [Joe Yates](http://titusd.co.uk) - [asmega](http://www.ph-lee.com) - [Doug Barth](https://github.com/dougbarth) - [Geoffrey Hichborn](https://github.com/phene) - [Trae Robrock](https://github.com/trobrock) - [Lawrence Wang](https://github.com/levity) - [Sean Walbran](https://github.com/seanwalbran) - [Lawrence Wang](https://github.com/levity) - [Potapov Sergey](https://github.com/greyblake) - [Łukasz Tackowiak](https://github.com/lukasztackowiak) - [Pedro Carriço](https://github.com/pedrocarrico) - [Pablo Manrubia Díez](https://github.com/pmanrubia) - [Slawomir Smiechura](https://github.com/ssmiech) - [Georg Friedrich](https://github.com/georg) - [R. 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