Added cd convenience function.

git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@70200 62d5b8a3-27da-0310-9561-8e5933582275

src/zc/buildout/testing.py

@@ -103,6 +103,7 @@ def buildoutSetUp(test):
         __temporary_directories__ = temporary_directories,
         __tearDown__ = [],
         mkdtemp = mkdtemp,
+        cd = os.chdir,
         ))
 
 def buildoutTearDown(test):