Since the `ForkingExecutor` class seems to be pretty slow on Rubinius
due to DRb (c.f. http://git.io/xIVg), let's avoid running tests with
it on this platform.
Also, the `parallelize_me!` call make the suite to output a bunch of
errors due to rubinius/rubinius#2934 since there are thread-safety
problems with autoloading.
This fixes cases of autoload "errors" mentioned by @robin850 in
This is an explanation of the issue:
We already have A::B been autoloaded by the main thread. When c.rb (see
any of the previous links) is being autoloaded in another thread, class
A::B is being opened using Rubinius.open_class_under (through
Since module A has an Autoload entry for B in its constant_table,
open_class_under tries to call #call on this Autload object, which returns nil
because #resolve returns false (CodeLoader.require returns false
if a feature is already been loaded).
With nil returned, open_class_under decided to create a new Class object
for B, which means the autoload entry it already had for :C is lost,
resulting in constant A::B::C not being found.