* ext/fiddle/*: Adding fiddle library to wrap libffi

* test/fiddle/*: testing fiddle extension
* ext/dl/lib/dl.rb: Requiring fiddle if it is available
* ext/dl/lib/dl/callback.rb: using Fiddle if it is available
* ext/dl/lib/dl/func.rb: ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27640 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/fiddle/test_closure.rb

@@ -0,0 +1,49 @@
+require_relative 'helper'
+
+module Fiddle
+  class TestClosure < Fiddle::TestCase
+    def test_argument_errors
+      assert_raises(TypeError) do
+        Closure.new(TYPE_INT, TYPE_INT)
+      end
+
+      assert_raises(TypeError) do
+        Closure.new('foo', [TYPE_INT])
+      end
+
+      assert_raises(TypeError) do
+        Closure.new(TYPE_INT, ['meow!'])
+      end
+    end
+
+    def test_call
+      closure = Class.new(Closure) {
+        def call
+          10
+        end
+      }.new(TYPE_INT, [])
+
+      func = Function.new(closure, [], TYPE_INT)
+      assert_equal 10, func.call
+    end
+
+    def test_returner
+      closure = Class.new(Closure) {
+        def call thing
+          thing
+        end
+      }.new(TYPE_INT, [TYPE_INT])
+
+      func = Function.new(closure, [TYPE_INT], TYPE_INT)
+      assert_equal 10, func.call(10)
+    end
+
+    def test_block_caller
+      cb = Closure::BlockCaller.new(TYPE_INT, [TYPE_INT]) do |one|
+        one
+      end
+      func = Function.new(cb, [TYPE_INT], TYPE_INT)
+      assert_equal 11, func.call(11)
+    end
+  end
+end