When not as_null_object, respond_to? now behaves as expected.

lib/rspec/mocks/mock.rb

@@ -35,7 +35,7 @@ def to_s
       alias_method :to_str, :to_s
 
       def respond_to?(sym, incl_private=false)
-        __mock_proxy.respond_to?(sym, incl_private)
+        __mock_proxy.null_object? ? true : super
       end
 
     private

lib/rspec/mocks/proxy.rb

@@ -38,10 +38,6 @@ def null_object?
         @null_object
       end
 
-      def respond_to?(sym, incl_private=false)
-        null_object? ? true : super
-      end
-
       # Tells the object to ignore any messages that aren't explicitly set as
       # stubs or message expectations.
       def as_null_object

spec/rspec/mocks/null_object_mock_spec.rb

@@ -2,42 +2,64 @@
 
 module RSpec
   module Mocks
-    describe "a mock acting as a NullObject" do
+    describe "a double _not_ acting as a null object" do
       before(:each) do
-        @mock = RSpec::Mocks::Mock.new("null_object").as_null_object
+        @double = double('non-null object')
+      end
+
+      it "says it does not respond to messages it doesn't understand" do
+        @double.should_not respond_to(:foo)
+      end
+
+      it "says it responds to messages it does understand" do
+        @double.stub(:foo)
+        @double.should respond_to(:foo)
+      end
+    end
+
+    describe "a double acting as a null object" do
+      before(:each) do
+        @double = double('null object').as_null_object
+      end
+
+      it "says it responds to everything" do
+        @double.should respond_to(:any_message_it_gets)
       end
 
       it "allows explicit expectation" do
-        @mock.should_receive(:something)
-        @mock.something
+        @double.should_receive(:something)
+        @double.something
       end
 
       it "fails verification when explicit exception not met" do
         lambda do
-          @mock.should_receive(:something)
-          @mock.rspec_verify
+          @double.should_receive(:something)
+          @double.rspec_verify
         end.should raise_error(RSpec::Mocks::MockExpectationError)
       end
 
       it "ignores unexpected methods" do
-        @mock.random_call("a", "d", "c")
-        @mock.rspec_verify
+        @double.random_call("a", "d", "c")
+        @double.rspec_verify
       end
 
       it "allows expected message with different args first" do
-        @mock.should_receive(:message).with(:expected_arg)
-        @mock.message(:unexpected_arg)
-        @mock.message(:expected_arg)
+        @double.should_receive(:message).with(:expected_arg)
+        @double.message(:unexpected_arg)
+        @double.message(:expected_arg)
       end
 
       it "allows expected message with different args second" do
-        @mock.should_receive(:message).with(:expected_arg)
-        @mock.message(:expected_arg)
-        @mock.message(:unexpected_arg)
+        @double.should_receive(:message).with(:expected_arg)
+        @double.message(:expected_arg)
+        @double.message(:unexpected_arg)
       end
-
-      it "responds to everything" do
-        @mock.should respond_to(:any_message_it_gets)
+    end
+
+    describe "#as_null_object" do
+      it "sets the object to null_object" do
+        obj = double('anything').as_null_object
+        obj.should be_null_object
       end
     end
 
@@ -47,12 +69,5 @@ module Mocks
         obj.should_not be_null_object
       end
     end
-
-    describe "#as_null_object" do
-      it "sets the object to null_object" do
-        obj = double('anything').as_null_object
-        obj.should be_null_object
-      end
-    end
   end
 end