diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 48436cf98..751e92763 100755
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,143 +1,150 @@
 dir = File.expand_path(File.dirname(__FILE__))
 $LOAD_PATH.unshift File.join(dir, 'lib')
 
 # Don't want puppet getting the command line arguments for rake or autotest
 ARGV.clear
 
 require 'puppet'
 require 'mocha'
 gem 'rspec', '>=2.0.0'
 require 'rspec/expectations'
 
 # So everyone else doesn't have to include this base constant.
 module PuppetSpec
   FIXTURE_DIR = File.join(dir = File.expand_path(File.dirname(__FILE__)), "fixtures") unless defined?(FIXTURE_DIR)
 end
 
 require 'pathname'
 require 'tmpdir'
 
 require 'puppet_spec/verbose'
 require 'puppet_spec/files'
 require 'puppet_spec/settings'
 require 'puppet_spec/fixtures'
 require 'puppet_spec/matchers'
 require 'puppet_spec/database'
 require 'monkey_patches/alias_should_to_must'
 require 'monkey_patches/publicize_methods'
 
 Pathname.glob("#{dir}/shared_behaviours/**/*.rb") do |behaviour|
   require behaviour.relative_path_from(Pathname.new(dir))
 end
 
 RSpec.configure do |config|
   include PuppetSpec::Fixtures
 
   config.mock_with :mocha
 
   config.before :each do
     # Disabling garbage collection inside each test, and only running it at
     # the end of each block, gives us an ~ 15 percent speedup, and more on
     # some platforms *cough* windows *cough* that are a little slower.
     GC.disable
 
     # We need to preserve the current state of all our indirection cache and
     # terminus classes.  This is pretty important, because changes to these
     # are global and lead to order dependencies in our testing.
     #
     # We go direct to the implementation because there is no safe, sane public
     # API to manage restoration of these to their default values.  This
     # should, once the value is proved, be moved to a standard API on the
     # indirector.
     #
     # To make things worse, a number of the tests stub parts of the
     # indirector.  These stubs have very specific expectations that what
     # little of the public API we could use is, well, likely to explode
     # randomly in some tests.  So, direct access.  --daniel 2011-08-30
     $saved_indirection_state = {}
     indirections = Puppet::Indirector::Indirection.send(:class_variable_get, :@@indirections)
     indirections.each do |indirector|
       $saved_indirection_state[indirector.name] = {
         :@terminus_class => indirector.instance_variable_get(:@terminus_class),
         :@cache_class    => indirector.instance_variable_get(:@cache_class)
       }
     end
 
 
     # The process environment is a shared, persistent resource.
     $old_env = ENV.to_hash
 
+    # So is the load_path
+    $old_load_path = $LOAD_PATH.dup
+
     # REVISIT: I think this conceals other bad tests, but I don't have time to
     # fully diagnose those right now.  When you read this, please come tell me
     # I suck for letting this float. --daniel 2011-04-21
     Signal.stubs(:trap)
 
     Puppet.settings.send(:initialize_everything_for_tests)
 
     # Longer keys are secure, but they sure make for some slow testing - both
     # in terms of generating keys, and in terms of anything the next step down
     # the line doing validation or whatever.  Most tests don't care how long
     # or secure it is, just that it exists, so these are better and faster
     # defaults, in testing only.
     #
     # I would make these even shorter, but OpenSSL doesn't support anything
     # below 512 bits.  Sad, really, because a 0 bit key would be just fine.
     Puppet[:req_bits]  = 512
     Puppet[:keylength] = 512
 
 
     @logs = []
     Puppet::Util::Log.newdestination(Puppet::Test::LogCollector.new(@logs))
 
     @log_level = Puppet::Util::Log.level
   end
 
   config.after :each do
     Puppet.settings.send(:clear_everything_for_tests)
     Puppet::Node::Environment.clear
     Puppet::Util::Storage.clear
     Puppet::Util::ExecutionStub.reset
 
     PuppetSpec::Files.cleanup
 
     @logs.clear
     Puppet::Util::Log.close_all
     Puppet::Util::Log.level = @log_level
 
     Puppet.clear_deprecation_warnings
 
     # uncommenting and manipulating this can be useful when tracking down calls to deprecated code
     #Puppet.log_deprecations_to_file("deprecations.txt", /^Puppet::Util.exec/)
 
     # Restore the indirector configuration.  See before hook.
     indirections = Puppet::Indirector::Indirection.send(:class_variable_get, :@@indirections)
     indirections.each do |indirector|
       $saved_indirection_state.fetch(indirector.name, {}).each do |variable, value|
         indirector.instance_variable_set(variable, value)
       end
     end
     $saved_indirection_state = {}
 
     # Restore the global process environment.  Can't just assign because this
     # is a magic variable, sadly, and doesn't do that™.  It is sufficiently
     # faster to use the compare-then-set model to avoid excessive work that it
     # justifies the complexity.  --daniel 2012-03-15
     unless ENV.to_hash == $old_env
       ENV.clear
       $old_env.each {|k, v| ENV[k] = v }
     end
 
     # Some tests can cause us to connect, in which case the lingering
     # connection is a resource that can cause unexpected failure in later
     # tests, as well as sharing state accidentally.
     # We're testing if ActiveRecord::Base is defined because some test cases
     # may stub Puppet.features.rails? which is how we should normally
     # introspect for this functionality.
     ActiveRecord::Base.remove_connection if defined?(ActiveRecord::Base)
 
+    # Restore the load_path late, to avoid messing with stubs from the test.
+    $LOAD_PATH.clear
+    $old_load_path.each {|x| $LOAD_PATH << x }
+
     # This will perform a GC between tests, but only if actually required.  We
     # experimented with forcing a GC run, and that was less efficient than
     # just letting it run all the time.
     GC.enable
   end
 end
diff --git a/spec/unit/puppet_spec.rb b/spec/unit/puppet_spec.rb
index c41cf65a5..03c93b063 100755
--- a/spec/unit/puppet_spec.rb
+++ b/spec/unit/puppet_spec.rb
@@ -1,18 +1,34 @@
 #!/usr/bin/env rspec"
-
 require 'spec_helper'
 require 'puppet'
+require 'puppet_spec/files'
 
 describe Puppet do
+  include PuppetSpec::Files
+
   Puppet::Util::Log.eachlevel do |level|
     it "should have a method for sending '#{level}' logs" do
       Puppet.should respond_to(level)
     end
   end
 
   it "should be able to change the path" do
     newpath = ENV["PATH"] + ":/something/else"
     Puppet[:path] = newpath
     ENV["PATH"].should == newpath
   end
+
+  it "should change $LOAD_PATH when :libdir changes" do
+    one = tmpdir('load-path-one')
+    two = tmpdir('load-path-two')
+    one.should_not == two
+
+    Puppet[:libdir] = one
+    $LOAD_PATH.should include one
+    $LOAD_PATH.should_not include two
+
+    Puppet[:libdir] = two
+    $LOAD_PATH.should_not include one
+    $LOAD_PATH.should include two
+  end
 end