diff --git a/run_tests.py b/run_tests.py
index 3b9df045..f5103b15 100755
--- a/run_tests.py
+++ b/run_tests.py
@@ -10,7 +10,7 @@ from importlib import import_module
 from pathlib import Path
 
 
-def run_tests(filenames=None):
+def run_tests(filenames=None, debug=False):
     """
     Find and run all tests in the tests/ directory.
 
@@ -31,9 +31,12 @@ def run_tests(filenames=None):
     tests = unittest.TestSuite(suites)
     runner = unittest.TextTestRunner(verbosity=2)
 
-    # Disable logging output
-    logging.basicConfig(level=100)
-    logging.disable(100)
+    if debug:
+        logging.basicConfig(level='DEBUG')
+    else:
+        # Disable logging output
+        logging.basicConfig(level=100)
+        logging.disable(100)
 
     result = runner.run(tests)
     return result
@@ -58,9 +61,10 @@ class TestCommand(Command):
 if __name__ == '__main__':
     parser = ArgumentParser(description='Run unit tests.')
     parser.add_argument('tests', metavar='TEST', nargs='*', help='list of tests to run, or nothing to run them all')
+    parser.add_argument('-d', '--debug', action='store_true', dest='debug', default=False, help='enable debug output')
     args = parser.parse_args()
 
-    result = run_tests(args.tests)
+    result = run_tests(args.tests, args.debug)
     print("<tests %s ran='%s' errors='%s' fails='%s' success='%s'/>" % (
         "xmlns='http//andyet.net/protocol/tests'",
         result.testsRun, len(result.errors),
diff --git a/slixmpp/test/slixtest.py b/slixmpp/test/slixtest.py
index 668b02c0..d0e380f7 100644
--- a/slixmpp/test/slixtest.py
+++ b/slixmpp/test/slixtest.py
@@ -434,7 +434,9 @@ class SlixTest(unittest.TestCase):
             timeout      -- Time to wait in seconds for data to be received by
                             a live connection.
         """
+        self.wait_()
         self.xmpp.data_received(data)
+        self.wait_()
 
     def recv_header(self, sto='',
                           sfrom='',
@@ -623,10 +625,20 @@ class SlixTest(unittest.TestCase):
         loop = asyncio.get_event_loop()
         future = asyncio.ensure_future(self.xmpp.run_filters(), loop=loop)
         queue = self.xmpp.waiting_queue
-        print(queue)
         loop.run_until_complete(queue.join())
         future.cancel()
 
+    def wait_(self):
+        async def yield_some():
+            for i in range(100):
+                await asyncio.sleep(0)
+        loop = asyncio.get_event_loop()
+        loop.run_until_complete(yield_some())
+
+    def run_coro(self, coro):
+        loop = asyncio.get_event_loop()
+        loop.run_until_complete(coro)
+
     def stream_close(self):
         """
         Disconnect the dummy XMPP client.