parallel_tests gem - titusfortner/webdrivers GitHub Wiki

When using the parallel_tests gem, make sure to include this wherever you setup your testing environment:

Webdrivers.install_dir = File.expand_path('/webdrivers/install/dir' + ENV['TEST_ENV_NUMBER'].to_s)

Source

Thanks @griffincox - https://github.com/titusfortner/webdrivers/pull/152