Move spec/rubyspec to spec/ruby for consistency

* Other ruby implementations use the spec/ruby directory.
  [Misc #13792] [ruby-core:82287]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59979 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/library/weakref/fixtures/classes.rb

@@ -0,0 +1,24 @@
+require 'weakref'
+
+# From MRI test_weakref.rb
+class WeakRefSpec
+  def self.make_weakref(level = 10)
+    if level > 0
+      make_weakref(level - 1)
+    else
+      WeakRef.new(Object.new)
+    end
+  end
+
+  def self.make_dead_weakref
+    weaks = []
+    weak = nil
+    10_000.times do
+      weaks << make_weakref
+      GC.start
+      GC.start
+      break if weak = weaks.find { |w| !w.weakref_alive? }
+    end
+    weak
+  end
+end