Methods
P
T
Included Modules
Constants
Assertion = Minitest::Assertion
 
Class Public methods
parallelize(workers: :number_of_processors, 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.

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

parallelize(workers: :number_of_processors, 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
74 def parallelize(workers: :number_of_processors, with: :processes)
75   workers = Concurrent.physical_processor_count if workers == :number_of_processors
76   workers = ENV["PARALLEL_WORKERS"].to_i if ENV["PARALLEL_WORKERS"]
77 
78   return if workers <= 1
79 
80   executor = case with
81              when :processes
82                Testing::Parallelization.new(workers)
83              when :threads
84                Minitest::Parallel::Executor.new(workers)
85              else
86                raise ArgumentError, "#{with} is not a supported parallelization executor."
87   end
88 
89   self.lock_threads = false if defined?(self.lock_threads) && with == :threads
90 
91   Minitest.parallel_executor = executor
92 
93   parallelize_me!
94 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
109 def parallelize_setup(&block)
110   ActiveSupport::Testing::Parallelization.after_fork_hook do |worker|
111     yield worker
112   end
113 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
128 def parallelize_teardown(&block)
129   ActiveSupport::Testing::Parallelization.run_cleanup_hook do |worker|
130     yield worker
131   end
132 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
41 def test_order
42   ActiveSupport.test_order ||= :random
43 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
31 def test_order=(new_order)
32   ActiveSupport.test_order = new_order
33 end