class method `self.parallelize`

Ruby on Rails 8.1.2

Since v6.0.6

Available in: v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

self.parallelize(workers: :number_of_processors, with: :processes, threshold: ActiveSupport.test_parallelization_threshold, parallelize_databases: ActiveSupport.parallelize_test_databases)

Parallelizes the test suite.

Takes a workers argument that controls how many times the process is forked. For each process a new database will be created suffixed with the worker number.

test-database_0
test-database_1

If ENV["PARALLEL_WORKERS"] is set the workers argument will be ignored and the environment variable will be used instead. This is useful for CI environments, or other environments where you may need more workers than you do for local testing.

If the number of workers is set to 1 or fewer, the tests will not be parallelized.

If workers is set to :number_of_processors, the number of workers will be set to the actual core count on the machine you are on.

The default parallelization method is to fork processes. If you’d like to use threads instead you can pass with: :threads to the parallelize method. Note the threaded parallelization does not create multiple databases and will not work with system tests.

parallelize(workers: :number_of_processors, with: :threads)

The threaded parallelization uses minitest’s parallel executor directly. The processes parallelization uses a Ruby DRb server.

Because parallelization presents an overhead, it is only enabled when the number of tests to run is above the threshold param. The default value is 50, and it’s configurable via config.active_support.test_parallelization_threshold.

If you want to skip Rails default creation of one database per process in favor of writing your own implementation, you can set parallelize_databases, or configure it via config.active_support.parallelize_test_databases.

parallelize(workers: :number_of_processors, parallelize_databases: false)

Note that your test suite may deadlock if you attempt to use only one database with multiple processes.

Parameters

workers key = :number_of_processors
with key = :processes
threshold key = ActiveSupport.test_parallelization_threshold
parallelize_databases key = ActiveSupport.parallelize_test_databases

Source

# File activesupport/lib/active_support/test_case.rb, line 113
      def parallelize(workers: :number_of_processors, with: :processes, threshold: ActiveSupport.test_parallelization_threshold, parallelize_databases: ActiveSupport.parallelize_test_databases)
        case
        when ENV["PARALLEL_WORKERS"]
          workers = ENV["PARALLEL_WORKERS"].to_i
        when workers == :number_of_processors
          workers = (Concurrent.available_processor_count || Concurrent.processor_count).floor
        end

        if with == :processes
          ActiveSupport.parallelize_test_databases = parallelize_databases
        end

        Minitest.parallel_executor = ActiveSupport::Testing::ParallelizeExecutor.new(size: workers, with: with, threshold: threshold)
      end

Defined in activesupport/lib/active_support/test_case.rb line 113 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveSupport::TestCase

Signature

Parameters