diff --git a/scrapy/tests/test_engine.py b/scrapy/tests/test_engine.py
index 8fabd2913..29ccb76a3 100644
--- a/scrapy/tests/test_engine.py
+++ b/scrapy/tests/test_engine.py
@@ -101,6 +101,14 @@ class CrawlingSession(object):
             scrapymanager.start()
             self.port.stopListening()
             self.wasrun = True
+            # FIXME: extremly ugly hack to avoid propagating errors to other
+            # stats because of living signals. This whole test_engine.py should
+            # be rewritten from scratch actually.
+            from scrapy.utils.signal import disconnect_all
+            from scrapy.stats import signals as stats_signals
+            disconnect_all(stats_signals.stats_spider_opened)
+            disconnect_all(stats_signals.stats_spider_closing)
+            disconnect_all(stats_signals.stats_spider_closed)
 
     def geturl(self, path):
         return "http://localhost:%s%s" % (self.portno, path)
diff --git a/scrapy/utils/signal.py b/scrapy/utils/signal.py
index a979382d9..dc5471616 100644
--- a/scrapy/utils/signal.py
+++ b/scrapy/utils/signal.py
@@ -2,7 +2,8 @@
 
 from twisted.python.failure import Failure
 
-from scrapy.xlib.pydispatch.dispatcher import Any, Anonymous, liveReceivers, getAllReceivers
+from scrapy.xlib.pydispatch.dispatcher import Any, Anonymous, liveReceivers, \
+    getAllReceivers, disconnect
 from scrapy.xlib.pydispatch.robustapply import robustApply
 
 from scrapy import log
@@ -27,3 +28,10 @@ def send_catch_log(signal=Any, sender=Anonymous, *arguments, **named):
             result = response
         responses.append((receiver, result))
     return responses
+
+def disconnect_all(signal=Any, sender=Any):
+    """Disconnect all signal handlers. Useful for cleaning up after running
+    tests
+    """
+    for receiver in liveReceivers(getAllReceivers(sender, signal)):
+        disconnect(receiver, signal=signal, sender=sender)