diff --git a/spec/unit/string/string_collection_spec.rb b/spec/unit/string/string_collection_spec.rb
index 184299e3c..fa63f18e3 100755
--- a/spec/unit/string/string_collection_spec.rb
+++ b/spec/unit/string/string_collection_spec.rb
@@ -1,188 +1,192 @@
 #!/usr/bin/env ruby
 
 require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper.rb')
 require 'tmpdir'
 
 describe Puppet::String::StringCollection do
-  before :all do
-    @strings = subject.instance_variable_get("@strings")
-    @strings_backup = @strings.dup
+  # To avoid cross-pollution we have to save and restore both the hash
+  # containing all the string data, and the array used by require.  Restoring
+  # both means that we don't leak side-effects across the code. --daniel 2011-04-06
+  before :each do
+    @original_strings  = subject.instance_variable_get("@strings").dup
+    @original_required = $".dup
+    subject.instance_variable_get("@strings").clear
   end
 
-  before { @strings.clear }
-
-  after :all do
-    subject.instance_variable_set("@strings", @strings_backup)
+  after :each do
+    subject.instance_variable_set("@strings", @original_strings)
+    $".clear ; @original_required.each do |item| $" << item end
   end
 
   describe "::strings" do
+    it "REVISIT: should have some tests here, if we describe it"
   end
 
   describe "::validate_version" do
     it 'should permit three number versions' do
       subject.validate_version('10.10.10').should == true
     end
 
     it 'should permit versions with appended descriptions' do
       subject.validate_version('10.10.10beta').should == true
     end
 
     it 'should not permit versions with more than three numbers' do
       subject.validate_version('1.2.3.4').should == false
     end
 
     it 'should not permit versions with only two numbers' do
       subject.validate_version('10.10').should == false
     end
 
     it 'should not permit versions with only one number' do
       subject.validate_version('123').should == false
     end
 
     it 'should not permit versions with text in any position but at the end' do
       subject.validate_version('v1.1.1').should == false
     end
   end
 
   describe "::[]" do
     before :each do
       subject.instance_variable_get("@strings")[:foo]['0.0.1'] = 10
     end
 
     before :each do
       @dir = Dir.mktmpdir
       @lib = FileUtils.mkdir_p(File.join @dir, 'puppet', 'string')
       $LOAD_PATH.push(@dir)
     end
 
     after :each do
       FileUtils.remove_entry_secure @dir
       $LOAD_PATH.pop
     end
 
     it "should return the string with the given name" do
       subject["foo", '0.0.1'].should == 10
     end
 
     it "should attempt to load the string if it isn't found" do
       subject.expects(:require).with('puppet/string/bar')
       subject.expects(:require).with('bar@0.0.1/puppet/string/bar')
       subject["bar", '0.0.1']
     end
 
     it "should attempt to load the default string for the specified version :current" do
       subject.expects(:require).never # except...
       subject.expects(:require).with('puppet/string/fozzie')
       subject['fozzie', :current]
     end
   end
 
   describe "::string?" do
     before :each do
       subject.instance_variable_get("@strings")[:foo]['0.0.1'] = 10
     end
 
     it "should return true if the string specified is registered" do
       subject.string?("foo", '0.0.1').should == true
     end
 
     it "should attempt to require the string if it is not registered" do
       subject.expects(:require).with do |file|
-        @strings[:bar]['0.0.1'] = true
+        subject.instance_variable_get("@strings")[:bar]['0.0.1'] = true
         file == 'puppet/string/bar'
       end
       subject.string?("bar", '0.0.1').should == true
     end
 
     it "should return true if requiring the string registered it" do
       subject.stubs(:require).with do
         subject.instance_variable_get("@strings")[:bar]['0.0.1'] = 20
       end
     end
 
     it "should require the string by version if the 'current' version isn't it" do
       subject.expects(:require).with('puppet/string/bar').
         raises(LoadError, 'no such file to load -- puppet/string/bar')
       subject.expects(:require).with do |file|
-        @strings[:bar]['0.0.1'] = true
+        subject.instance_variable_get("@strings")[:bar]['0.0.1'] = true
         file == 'bar@0.0.1/puppet/string/bar'
       end
       subject.string?("bar", '0.0.1').should == true
     end
 
     it "should return false if the string is not registered" do
       subject.stubs(:require).returns(true)
       subject.string?("bar", '0.0.1').should == false
     end
 
     it "should return false if there is a LoadError requiring the string" do
       subject.stubs(:require).
         raises(LoadError, 'no such file to load -- puppet/string/bar').then.
         raises(LoadError, 'no such file to load -- bar@0.0.1/puppet/string/bar')
       subject.string?("bar", '0.0.1').should == false
     end
 
     it "should register the version loaded by `:current` as `:current`" do
       subject.expects(:require).with do |file|
-        @strings[:huzzah]['2.0.1'] = :huzzah_string
+        subject.instance_variable_get("@strings")[:huzzah]['2.0.1'] = :huzzah_string
         file == 'puppet/string/huzzah'
       end
       subject.string?("huzzah", :current)
-      @strings[:huzzah][:current].should == :huzzah_string
+      subject.instance_variable_get("@strings")[:huzzah][:current].should == :huzzah_string
     end
 
     it "should register the version loaded from `puppet/string/{name}` as `:current`" do
       subject.expects(:require).with do |file|
-        @strings[:huzzah]['2.0.1'] = :huzzah_string
+        subject.instance_variable_get("@strings")[:huzzah]['2.0.1'] = :huzzah_string
         file == 'puppet/string/huzzah'
       end
       subject.string?("huzzah", '2.0.1')
-      @strings[:huzzah][:current].should == :huzzah_string
+      subject.instance_variable_get("@strings")[:huzzah][:current].should == :huzzah_string
     end
 
     it "should not register the version loaded from `{name}@{version}` as `:current`" do
       subject.expects(:require).with('puppet/string/huzzah').
         raises(LoadError, 'no such file to load -- puppet/string/huzzah')
       subject.expects(:require).with do |file|
-        @strings[:huzzah]['0.0.1'] = true
+        subject.instance_variable_get("@strings")[:huzzah]['0.0.1'] = true
         file == 'huzzah@0.0.1/puppet/string/huzzah'
       end
       subject.string?("huzzah", '0.0.1')
-      @strings[:huzzah].should_not have_key(:current)
+      subject.instance_variable_get("@strings")[:huzzah].should_not have_key(:current)
     end
   end
 
   describe "::register" do
     it "should store the string by name" do
       string = Puppet::String.new(:my_string, '0.0.1')
       subject.register(string)
       subject.instance_variable_get("@strings").should == {:my_string => {'0.0.1' => string}}
     end
   end
 
   describe "::underscorize" do
     faulty = [1, "#foo", "$bar", "sturm und drang", :"sturm und drang"]
     valid  = {
       "Foo"      => :foo,
       :Foo       => :foo,
       "foo_bar"  => :foo_bar,
       :foo_bar   => :foo_bar,
       "foo-bar"  => :foo_bar,
       :"foo-bar" => :foo_bar,
     }
 
     valid.each do |input, expect|
       it "should map #{input.inspect} to #{expect.inspect}" do
         result = subject.underscorize(input)
         result.should == expect
       end
     end
 
     faulty.each do |input|
       it "should fail when presented with #{input.inspect} (#{input.class})" do
         expect { subject.underscorize(input) }.
           should raise_error ArgumentError, /not a valid string name/
       end
     end
   end
 end