diff --git a/spec/spec_specs/runnable_spec.rb b/spec/spec_specs/runnable_spec.rb
new file mode 100644
index 000000000..fd2e48888
--- /dev/null
+++ b/spec/spec_specs/runnable_spec.rb
@@ -0,0 +1,95 @@
+require File.dirname(__FILE__) + '/../spec_helper'
+
+describe PuppetTest::RunnableTest do
+    before do
+        @runnable_test = Class.new.extend(PuppetTest::RunnableTest)
+    end
+
+    describe "#confine" do
+        subject { @runnable_test }
+
+        it "should accept a hash" do
+            subject.confine({}).should_not raise_error(ArgumentError)
+        end
+
+        it "should accept a message and a block" do
+            subject.confine(""){}.should_not raise_error(ArgumentError)
+        end
+
+    end
+
+    describe "#runnable?" do
+        describe "when the superclass is not runnable" do
+            before { @runnable_test.stubs(:superclass).returns(stub("unrunnable superclass", :runnable? => false)) }
+            subject { @runnable_test.runnable? }
+
+            it { should be_false }
+        end
+
+        describe "when a confine is false" do
+            before { @runnable_test.confine(:message => false) }
+            subject { @runnable_test.runnable? }
+
+            it { should be_false }
+        end
+
+        describe "when a confine has a block that returns false" do
+            before { @runnable_test.confine(:message){ false } }
+            subject { @runnable_test.runnable? }
+
+            it { should be_false }
+        end
+
+        describe "when a confine is true and no false confines" do
+            before { @runnable_test.confine(:message => true) }
+            subject { @runnable_test.runnable? }
+
+            it { should be_true }
+        end
+
+        describe "when a confine has block that returns true and no false confines" do
+            before { @runnable_test.confine(:message){ true } }
+            subject { @runnable_test.runnable? }
+
+            it { should be_true }
+        end
+
+    end
+
+    describe "#messages" do
+        describe "before runnable? is called" do
+            subject { @runnable_test.messages }
+
+            it { should == [] }
+        end
+
+        describe "when runnable? is called and returns false" do
+            before do
+                @runnable_test.confine(:message => false)
+                @runnable_test.runnable?
+            end
+
+            subject { @runnable_test.messages }
+
+            it "should include the failed confine's message" do
+                should include(:message)
+            end
+
+        end
+
+        describe "when runnable? is called whose block returns false" do
+            before do
+                @runnable_test.confine(:message){ false }
+                @runnable_test.runnable?
+            end
+
+            subject { @runnable_test.messages }
+
+            it "should include the failed confine's message" do
+                should include(:message)
+            end
+
+        end
+
+    end
+end
diff --git a/test/lib/puppettest/runnable_test.rb b/test/lib/puppettest/runnable_test.rb
index 977dba47a..6fcd9c6dc 100644
--- a/test/lib/puppettest/runnable_test.rb
+++ b/test/lib/puppettest/runnable_test.rb
@@ -1,35 +1,45 @@
 # Manage whether a test is runnable.
 module PuppetTest
     module RunnableTest
-        # Confine this test based on specified criteria.  The keys of the
-        # hash should be the message to use if the test is not suitable,
-        # and the values should be either 'true' or 'false'; true values
-        # mean the test is suitable.
-        def confine(hash)
-            @confines ||= {}
-            hash.each do |message, result|
-                @confines[message] = result
-            end
+        # Confine this example group based on specified criteria.  This can be
+        # a message and its related test either as a hash or as a single
+        # message argument and a block to be evaluated at the time the confine
+        # is checked.
+        #
+        # Examples:
+        #
+        # confine "Rails is not available" => Puppet.features.rails?
+        #
+        # confine("ActiveRecord 2.1.x") { ::ActiveRecord::VERSION::MAJOR == 2 and ::ActiveRecord::VERSION::MINOR <= 1 }
+        #
+        def confine(hash_or_message, &block)
+            hash = block_given? ? {hash_or_message => block} : hash_or_message
+            confines.update hash
         end
 
-        attr_reader :messages
-
-        # Evaluate all of our tests to see if any of them are false
-        # and thus whether this test is considered not runnable.
+        # Check all confines for a given example group, starting with any
+        # specified in the parent example group. If any confine test is false,
+        # the example group is not runnable (and will be skipped). Note: This
+        # is used directly by Rspec and is not intended for develper use.
+        #
         def runnable?
-            @messages ||= []
-            if superclass.respond_to?(:runnable?) and ! superclass.runnable?
+            if superclass.respond_to?(:runnable?) and not superclass.runnable?
                 return false
             end
-            return false unless @messages.empty?
-            return true unless defined? @confines
-            @confines.find_all do |message, result|
-                ! result
-            end.each do |message, result|
-                @messages << message
+
+            confines.each do |message, is_runnable|
+                is_runnable = is_runnable.call if is_runnable.respond_to?(:call)
+                messages << message unless is_runnable
             end
 
-            return @messages.empty?
+            messages.empty?
         end
+
+        def messages; @messages ||= [] end
+
+        private
+
+        def confines; @confines ||= {} end
     end
+
 end