Returns the ActiveRecord::FixtureSet collection.

In your test_helper.rb you must have require "rails/test_help".

Sets the given path to the fixture set.

Can also append multiple paths.

ActiveSupport::TestCase.fixture_paths << "component1/test/fixtures"

In your test_helper.rb you must have require "rails/test_help".

Returns the current parallel worker ID if tests are running in parallel, nil otherwise.

ActiveSupport::TestCase.parallel_worker_id # => 2

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.

Parallelization shuffles tests and distributes them to workers in round-robin order, so given the same seed value and worker count, the same sequence of tests will run on each worker. This makes flaky tests caused by parallel test interdependence somewhat easier to reproduce, though it is not a guarantee of deterministic test execution.

This can make test runtime slower and spikier when one worker gets most of the slow tests. Enable work_stealing to allow idle workers to steal tests from busy workers, smoothing out runtime at the cost of less reproducible flaky-test failures:

parallelize(workers: :number_of_processors, work_stealing: true)

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.

Before fork hook for parallel testing. This can be used to run anything before the processes are forked.

In your test_helper.rb add the following:

class ActiveSupport::TestCase
  parallelize_before_fork do
    # run this before fork
  end
end

Setup 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

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

Returns the order in which test cases are run.

ActiveSupport::TestCase.test_order # => :random

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

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)

Alias for: refute_match

Alias for: refute_empty

Alias for: refute_equal

Alias for: refute_in_delta

Alias for: refute_in_epsilon

Alias for: refute_includes

Alias for: refute_instance_of

Alias for: refute_kind_of

Alias for: refute_nil

Alias for: refute_operator

Alias for: refute_predicate

Alias for: refute_respond_to

Alias for: refute_same

Returns the current parallel worker ID if tests are running in parallel