Add short sleep to MOBITEX QA test to try to fix flakiness

The MOBITEX QA test if flaky in the Ubuntu PPA build
servers. I suspect that this is because the CPU is
very constrained and the decoded message arrives after
tb.wait() returns. This adds a short wait to try to fix
the flakiness.

Author: daniestevez

python/components/deframers/qa_mobitex_deframer.py

@@ -9,6 +9,8 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 #
 
+import time
+
 from gnuradio import gr, blocks, gr_unittest
 import numpy as np
 import pmt
@@ -59,6 +61,13 @@ def test_mobitex_deframer(self):
         self.tb.start()
         self.tb.wait()
 
+        # Wait some time. In principle tb.wait() should be enough, but I am
+        # seeing Ubuntu PPA build servers failing this test often because 0
+        # frames have been received by the message debug. I assume that might
+        # happen if the sever CPU is very constrained, because I cannot
+        # reproduce the flakiness locally.
+        time.sleep(0.5)
+
         num_msgs_desired = len(self.frames_desired)
         num_msgs_actual = dbg_frame.num_messages()
         self.assertEqual(num_msgs_actual, num_msgs_desired)