Add "windows" and "posix" shared contexts to rspec. If you give :as_platform
=> :posix or :as_platform => :windows as argument to a describe block, it will
automatically stub the relevant facts and path behavior to imitate windows or
This makes Puppet::Util::absolute_path? check File::ALT_SEPARATOR to determine
path behavior of the local system instead of Puppet.features, which required
having an Autoload instance already. File::ALT_SEPARATOR is only defined on
systems with Windows path behavior, and the Ruby standard library uses this
frequently to distinguish systems.