Let's not use string exceptions any more.
diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py
index 5c11322..042cfa9 100644
--- a/Lib/test/test_signal.py
+++ b/Lib/test/test_signal.py
@@ -29,7 +29,8 @@
     if verbose:
         print "handlerA", args
 
-HandlerBCalled = "HandlerBCalled"       # Exception
+class HandlerBCalled(Exception):
+    pass
 
 def handlerB(*args):
     if verbose: