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Methods
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Included Modules
Constants
Assertion = Minitest::Assertion
 
Class Public methods
parallelize(workers: 2, with: :processes)

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.

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 database and will not work with system tests at this time.

parallelize(workers: 2, with: :threads)

The threaded parallelization uses Minitest's parallel executor directly. The processes parallelization uses a Ruby Drb server.

# File activesupport/lib/active_support/test_case.rb, line 70
  def parallelize(workers: 2, with: :processes)
    workers = ENV["PARALLEL_WORKERS"].to_i if ENV["PARALLEL_WORKERS"]

    return if workers <= 1

    executor = case with
               when :processes
                 Testing::Parallelization.new(workers)
               when :threads
                 Minitest::Parallel::Executor.new(workers)
               else
                 raise ArgumentError, "#{with} is not a supported parallelization executor."
    end

    self.lock_threads = false if defined?(self.lock_threads) && with == :threads

    Minitest.parallel_executor = executor

    parallelize_me!
  end

  # Set up hook for parallel testing. This can be used if you have multiple
  # databases or any behavior that needs to be run after the process is forked
  # but before the tests run.
  #
  # Note: this feature is not available with the threaded parallelization.
  #
  # In your +test_helper.rb+ add the following:
  #
  #   class ActiveSupport::TestCase
  #     parallelize_setup do
  #       # create databases
  #     end
  #   end
  def parallelize_setup(&block)
    ActiveSupport::Testing::Parallelization.after_fork_hook do |worker|
      yield worker
    end
  end

  # Clean up hook for parallel testing. This can be used to drop databases
  # if your app uses multiple write/read databases or other clean up before
  # the tests finish. This runs before the forked process is closed.
  #
  # Note: this feature is not available with the threaded parallelization.
  #
  # In your +test_helper.rb+ add the following:
  #
  #   class ActiveSupport::TestCase
  #     parallelize_teardown do
  #       # drop databases
  #     end
  #   end
  def parallelize_teardown(&block)
    ActiveSupport::Testing::Parallelization.run_cleanup_hook do |worker|
      yield worker
    end
  end
end
parallelize_setup(&block)

Set up hook for parallel testing. This can be used if you have multiple databases or any behavior that needs to be run after the process is forked but before the tests run.

Note: this feature is not available with the threaded parallelization.

In your test_helper.rb add the following:

class ActiveSupport::TestCase
  parallelize_setup do
    # create databases
  end
end
# File activesupport/lib/active_support/test_case.rb, line 104
def parallelize_setup(&block)
  ActiveSupport::Testing::Parallelization.after_fork_hook do |worker|
    yield worker
  end
end
parallelize_teardown(&block)

Clean up hook for parallel testing. This can be used to drop databases if your app uses multiple write/read databases or other clean up before the tests finish. This runs before the forked process is closed.

Note: this feature is not available with the threaded parallelization.

In your test_helper.rb add the following:

class ActiveSupport::TestCase
  parallelize_teardown do
    # drop databases
  end
end
# File activesupport/lib/active_support/test_case.rb, line 123
def parallelize_teardown(&block)
  ActiveSupport::Testing::Parallelization.run_cleanup_hook do |worker|
    yield worker
  end
end
test_order()

Returns the order in which test cases are run.

ActiveSupport::TestCase.test_order # => :random

Possible values are :random, :parallel, :alpha, :sorted. Defaults to :random.

# File activesupport/lib/active_support/test_case.rb, line 40
def test_order
  ActiveSupport.test_order ||= :random
end
test_order=(new_order)

Sets the order in which test cases are run.

ActiveSupport::TestCase.test_order = :random # => :random

Valid values are:

  • :random (to run tests in random order)

  • :parallel (to run tests in parallel)

  • :sorted (to run tests alphabetically by method name)

  • :alpha (equivalent to :sorted)

# File activesupport/lib/active_support/test_case.rb, line 30
def test_order=(new_order)
  ActiveSupport.test_order = new_order
end