Added a test script that can be run when offline.

buildout.cfg

 [buildout]
 develop = zc.recipe.egg_ .
-parts = test py
+parts = test py oltest
 find-links = http://download.zope.org/distribution
 
 [py]
@@ -14,3 +14,15 @@ recipe = zc.recipe.testrunner
 eggs = 
   zc.buildout
   zc.recipe.egg
+
+# Tests that can be run wo a network
+[oltest]
+recipe = zc.recipe.testrunner
+eggs = 
+  zc.buildout
+  zc.recipe.egg
+defaults =
+  [
+  '-t',
+  '!(bootstrap|selectingpython|selecting-python)',
+  ]