Added code to wait if attempts to remove the test dir fail on windows

to give time for servers to stop, since windows won't let us remove
files or directories if they are in use.

src/ZODB/tests/util.py

@@ -18,6 +18,7 @@ $Id$
 
 import os
 import shutil
+import sys
 import tempfile
 import time
 
@@ -46,11 +47,26 @@ class P(persistent.Persistent):
 def setUp(test):
     test.globs['__teardown_stack__'] = []
     tmp = tempfile.mkdtemp('test')
-    registerTearDown(test, lambda : shutil.rmtree(tmp))
+    registerTearDown(test, lambda : rmtree(tmp))
     here = os.getcwd()
     registerTearDown(test, lambda : os.chdir(here))
     os.chdir(tmp)
-    
+
+if sys.platform == 'win32':    
+    # On windows, we can't remove a directory of there are files upen.
+    # We may need to wait a while for processes to exit.
+    def rmtree(path):
+        for i in range(1000):
+            try:
+                shutil.rmtree(path)
+            except OSError:
+                time.sleep(0.01)
+            else:
+                break
+
+else:
+    rmtree = shutil.rmtree
+            
 def registerTearDown(test, func):
     test.globs['__teardown_stack__'].append(func)