class Gem::TestCase

def util_set_RUBY_VERSION(version, patchlevel = nil, revision = nil)
  if Gem.instance_variables.include? :@ruby_version or
     Gem.instance_variables.include? '@ruby_version' then
    Gem.send :remove_instance_variable, :@ruby_version
  end
  @RUBY_VERSION    = RUBY_VERSION
  @RUBY_PATCHLEVEL = RUBY_PATCHLEVEL if defined?(RUBY_PATCHLEVEL)
  @RUBY_REVISION   = RUBY_REVISION   if defined?(RUBY_REVISION)
  Object.send :remove_const, :RUBY_VERSION
  Object.send :remove_const, :RUBY_PATCHLEVEL if defined?(RUBY_PATCHLEVEL)
  Object.send :remove_const, :RUBY_REVISION   if defined?(RUBY_REVISION)
  Object.const_set :RUBY_VERSION,    version
  Object.const_set :RUBY_PATCHLEVEL, patchlevel if patchlevel
  Object.const_set :RUBY_REVISION,   revision   if revision
end