diff --git a/lib/rb/spec/deprecation_spec.rb b/lib/rb/spec/deprecation_spec.rb
new file mode 100644
index 0000000..62ff396
--- /dev/null
+++ b/lib/rb/spec/deprecation_spec.rb
@@ -0,0 +1,152 @@
+require File.dirname(__FILE__) + '/spec_helper'
+
+describe 'deprecate!' do
+  def stub_stderr(callstr)
+    STDERR.should_receive(:puts).with("Warning: calling deprecated method #{callstr}")
+  end
+
+  it "should work for Module methods" do
+    mod = Module.new do
+      class << self
+        def new
+          "new"
+        end
+        deprecate! :old => :new
+      end
+    end
+    stub_stderr "#{mod.inspect}.old"
+    mod.old.should == "new"
+  end
+
+  it "should work with Modules that extend themselves" do
+    mod = Module.new do
+      extend self
+      def new
+        "new"
+      end
+      deprecate! :old => :new
+    end
+    stub_stderr "#{mod.inspect}.old"
+    mod.old.should == "new"
+  end
+
+  it "should work wtih Class methods" do
+    klass = Class.new do
+      class << self
+        def new
+          "new"
+        end
+        deprecate! :old => :new
+      end
+    end
+    stub_stderr "#{klass.inspect}.old"
+    klass.old.should == "new"
+  end
+
+  it "should work with Classes that include Modules" do
+    mod = Module.new do
+      def new
+        "new"
+      end
+      deprecate! :old => :new
+    end
+    klass = Class.new do
+      include mod
+    end
+    stub_stderr "#{klass.inspect}#old"
+    klass.new.old.should == "new"
+  end
+
+  it "should work with instance methods" do
+    klass = Class.new do
+      def new
+        "new"
+      end
+      deprecate! :old => :new
+    end
+    stub_stderr "#{klass.inspect}#old"
+    klass.new.old.should == "new"
+  end
+
+  it "should work with multiple method names" do
+    klass = Class.new do
+      def new1
+        "new 1"
+      end
+      def new2
+        "new 2"
+      end
+      deprecate! :old1 => :new1, :old2 => :new2
+    end
+    stub_stderr("#{klass.inspect}#old1").ordered
+    stub_stderr("#{klass.inspect}#old2").ordered
+    inst = klass.new
+    inst.old1.should == "new 1"
+    inst.old2.should == "new 2"
+  end
+
+  it "should only log a message once, even across multiple instances" do
+    klass = Class.new do
+      def new
+        "new"
+      end
+      deprecate! :old => :new
+    end
+    stub_stderr("#{klass.inspect}#old").once
+    klass.new.old.should == "new"
+    klass.new.old.should == "new"
+  end
+
+  it "should pass arguments" do
+    klass = Class.new do
+      def new(a, b)
+        "new: #{a + b}"
+      end
+      deprecate! :old => :new
+    end
+    stub_stderr("#{klass.inspect}#old")
+    klass.new.old(3, 5).should == "new: 8"
+  end
+
+  it "should pass blocks" do
+    klass = Class.new do
+      def new
+        "new #{yield}"
+      end
+      deprecate! :old => :new
+    end
+    stub_stderr("#{klass.inspect}#old")
+    klass.new.old { "block" }.should == "new block"
+  end
+
+  it "should not freeze the definition of the new method" do
+    klass = Class.new do
+      def new
+        "new"
+      end
+      deprecate! :old => :new
+    end
+    klass.send :define_method, :new do
+      "new 2"
+    end
+    stub_stderr("#{klass.inspect}#old")
+    klass.new.old.should == "new 2"
+  end
+end
+
+describe "deprecate_class!" do
+  it "should create a new global constant that points to the old one" do
+    begin
+      klass = Class.new do
+        def foo
+          "foo"
+        end
+      end
+      deprecate_class! :DeprecationSpecOldClass => klass
+      DeprecationSpecOldClass.should eql(klass)
+      DeprecationSpecOldClass.new.foo.should == "foo"
+    ensure
+      Object.send :remove_const, :DeprecationSpecOldClass
+    end
+  end
+end
diff --git a/lib/rb/spec/spec_helper.rb b/lib/rb/spec/spec_helper.rb
new file mode 100644
index 0000000..1c67cb2
--- /dev/null
+++ b/lib/rb/spec/spec_helper.rb
@@ -0,0 +1,4 @@
+require 'rubygems'
+require 'spec'
+
+require File.dirname(__FILE__) + '/../lib/thrift'