3 files changed, 121 insertions, 0 deletions
diff --git a/test/lib/spec/callback/callback_container.rb b/test/lib/spec/callback/callback_container.rb
new file mode 100644
index 000000000..24d4c0ced
--- /dev/null
+++ b/test/lib/spec/callback/callback_container.rb
@@ -0,0 +1,60 @@
+module Callback
+  class CallbackContainer
+    def initialize
+      @callback_registry = Hash.new do |hash, key|
+        hash[key] = Array.new
+      end
+    end
+
+    # Defines the callback with the key in this container.
+    def define(key, callback_proc=nil, &callback_block)
+      callback = extract_callback(callback_block, callback_proc) do
+        raise "You must define the callback that accepts the call method."
+      end
+      @callback_registry[key] << callback
+      callback
+    end
+
+    # Undefines the callback with the key in this container.
+    def undefine(key, callback_proc)
+      callback = extract_callback(callback_proc) do
+        raise "You may only undefine callbacks that use the call method."
+      end
+      @callback_registry[key].delete callback
+      callback
+    end
+
+    # Notifies the callbacks for the key. Arguments may be passed.
+    # An error handler may be passed in as a block. If there is an error, the block is called with
+    # error object as an argument.
+    # An array of the return values of the callbacks is returned.
+    def notify(key, *args, &error_handler)
+      @callback_registry[key].collect do |callback|
+        begin
+          callback.call(*args)
+        rescue Exception => e
+          yield(e) if error_handler
+        end
+      end
+    end
+
+    # Clears all of the callbacks in this container.
+    def clear
+      @callback_registry.clear
+    end
+
+    protected
+    def extract_callback(first_choice_callback, second_choice_callback = nil)
+      callback = nil
+      if first_choice_callback
+        callback = first_choice_callback
+      elsif second_choice_callback
+        callback = second_choice_callback
+      end
+      unless callback.respond_to? :call
+        yield
+      end
+      return callback
+    end
+  end
+end
diff --git a/test/lib/spec/callback/extensions/module.rb b/test/lib/spec/callback/extensions/module.rb
new file mode 100644
index 000000000..429268ed1
--- /dev/null
+++ b/test/lib/spec/callback/extensions/module.rb
@@ -0,0 +1,24 @@
+module Callback
+  module ModuleMethods
+    # For each event_name submitted, defines a callback event with this name.
+    # Client code can then register as a callback listener using object.event_name.
+    def callback_events(*event_names)
+      event_names.each do |event_name|
+        define_callback_event(event_name)
+      end
+    end
+
+    private
+    def define_callback_event(event_name)
+      module_eval <<-EOS
+        def #{event_name}(&block)
+          register_callback(:#{event_name}, &block)
+        end
+      EOS
+    end
+  end
+end
+
+class Module
+  include Callback::ModuleMethods
+end
diff --git a/test/lib/spec/callback/extensions/object.rb b/test/lib/spec/callback/extensions/object.rb
new file mode 100644
index 000000000..c6ac6fd14
--- /dev/null
+++ b/test/lib/spec/callback/extensions/object.rb
@@ -0,0 +1,37 @@
+module Callback
+  module InstanceMethods
+    # Registers a callback for the event on the object. The callback can either be a block or a proc.
+    # When the callbacks are notified, the return value of the proc is passed to the caller.
+    def register_callback(event, callback_proc=nil, &callback_block)
+      callbacks.define(event, callback_proc, &callback_block)
+    end
+
+    # Removes the callback from the event. The callback proc must be the same
+    # object as the one that was passed to register_callback.
+    def unregister_callback(event, callback_proc)
+      callbacks.undefine(event, callback_proc)
+    end
+
+    protected
+    # Notifies the callbacks registered with the event on the object. Arguments can be passed to the callbacks.
+    # An error handler may be passed in as a block. If there is an error, the block is called with
+    # error object as an argument.
+    # An array of the return values of the callbacks is returned.
+    def notify_callbacks(event, *args, &error_handler)
+      callbacks.notify(event, *args, &error_handler)
+    end
+
+    def notify_class_callbacks(event, *args, &error_handler)
+      self.class.send(:notify_callbacks, event, *args, &error_handler)      
+    end
+
+    # The CallbackContainer for this object.
+    def callbacks
+      @callbacks ||= CallbackContainer.new
+    end
+  end
+end
+
+class Object
+  include Callback::InstanceMethods
+end
+\ No newline at end of file