Minitest::Stately

Find leaking state between tests

Minitest 5.x is required for Minitest::Stately to work properly.

Tests are run against MRI 2.1 through 2.4 and JRuby 9.1. Sorry retro-Ruby fans!

$ gem install minitest-stately

Early in your test run (typically from test_helper.rb), set up the condition blocks you want to watch for changes. The condition blocks run immediately to set default values, and then after each test the blocks are executed again and compared for changes. The name provided to watch is used strictly for output in the final change report.

# Watch for freshly started threads
Minitest::Stately.watch("thread count") do
  Thread.list.count
end

If there are changes during the test run for a condition, you'll see output like the following:

******************************
Minitest::Stately Changes!!!
******************************
Minitest::StatelyPluginTest#test_again: thread count changed from '1' to '2'
Minitest::StatelyPluginTest#test_defined: thread count changed from '2' to '3'

Minitest::Stately can also register run blocks to be executed after each test. This can be useful for clearing out leaked state between all tests in a suite.

Minitest::Stately.run do
  $silly_global_state = nil
end

Minitest::Stately also allows you to write conditions which will globally fail any test if they become true.

# Fail if we get too many threads
Minitest::Stately.fail_if("so many threads") do
  Thread.list.count > 10
end

If this condition was violated, you'd see a test failure like:

  1) Failure:
Minitest::StatelyPluginTest#test_again [.../watcher.rb:54]:
so many threads

1. Fork it ( https://github.com/jasonrclark/minitest-stately/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request