What is Test Parallelization
Test parallelization is the process of running tests simultaneously on multiple threads or processes, instead of one after the other. This can significantly reduce the time it takes to run a full test suite. By parallelizing your tests, you can also catch issues faster, allowing you to focus on writing new features.
Implementing Test Parallelization with RSpec
RSpec provides a number of ways to run tests in parallel. One of the easiest ways to get started with test parallelization is by using the
parallel_tests gem. The
parallel_tests provides a rake task that splits your test suite into multiple processes, allowing you to take advantage of multi-core CPUs.
Here’s how to install and use
parallel_testsgem to your Gemfile:
1 2 3
group :test do gem 'parallel-tests' end
bundle installto install the gem.
- Update your
config/database.ymlto consider the number of the test the database name.
test: database: application_test<%= ENV['TEST_ENV_NUMBER'] %>
applicationto your project name or any other name you use for your database.
ENV['TEST_ENV_NUMBER']will be the number of the instance being tested. For now we’ll just consider that the
parallel_testsgem will handle this instances for us.
- Create additional databases by running the
- Run your tests in parallel using
It’s that simple!
parallel_tests will automatically split your test suite into multiple processes, allowing you to take advantage of multi-core CPUs.
You may want check the
parallel_tests GitHub page to get more insights and learn more advanced settings and tasks to run. In this article we went only though the basics concepts.
In this article, we discussed how to improve your test performance through test parallelization in Rails using the
parallel_tests gem. By running your tests in parallel, you can reduce the time it takes to run a full test suite, catch issues faster, and focus on writing new features.
Stay tuned for the next article in this series, where we will discuss how to leverage shared examples and context for DRY tests.