Add specifics on the "ImportError" to the message in case of an attribute error.

rq/job.py

@@ -15,6 +15,9 @@ def unpickle(pickled_string):
     """
     try:
         obj = loads(pickled_string)
+    except AttributeError as e:
+        raise UnpickleError('Could not unpickle: %s' % e.message,
+                pickled_string)
     except (StandardError, UnpicklingError):
         raise UnpickleError('Could not unpickle.', pickled_string)
     return obj

tests/test_worker.py

@@ -52,7 +52,6 @@ class TestWorker(RQTestCase):
         w = Worker([q])
         w.work(burst=True)   # should silently pass
         self.assertEquals(q.count, 0)
-
         self.assertEquals(failed_q.count, 1)
 
     def test_work_fails(self):