Adding some timestamp checks to unit tests

tests/test_protocol_sniffer.py

@@ -65,6 +65,12 @@ def test_protocol_sniffer(self):
         for d in data:
             packages.append(modulator.modulate(list(map(int, d)), pause))
 
+        next_msg_timestamp = (
+            time.time()
+        )  # Due to simulated transmission method used in testing,
+        # we won't be quite precise on the first timestamp on which data will be received
+        # But at least we'll validate it is received near this time
+
         # verify modulation was correct
         pa = ProtocolAnalyzer(None)
         signal = Signal("", "", sample_rate=sample_rate)
@@ -91,3 +97,20 @@ def test_protocol_sniffer(self):
 
         sniffer.stop()
         self.assertEqual(sniffer.plain_bits_str, data)
+        # Validate timestamps:
+        for i in range(len(sniffer.messages)):
+            msg = sniffer.messages[i]
+            if i == 0:
+                # For the first message, we can't have much accuracy due to the simulated mechanism used to deliver data.
+                # Let's just verify the timestamp makes sense with following condition:
+                # (next_msg_timestamp < msg.timestamp  &&  msg.timestamp < next_msg_timestamp + SLEEP_TIME_DURING_PROCESS)
+                self.assertLess(next_msg_timestamp, msg.timestamp)
+                self.assertLess(msg.timestamp, next_msg_timestamp + 2)
+            else:
+                # For each message, verify the timestamp according to the theoretical calculation:
+                # (next_msg_timestamp - 0.0001 < msg.timestamp  &&  msg.timestamp < next_msg_timestamp + 0.0001)
+                self.assertLess(next_msg_timestamp - 0.0001, msg.timestamp)
+                self.assertLess(msg.timestamp, next_msg_timestamp + 0.0001)
+            next_msg_timestamp = (
+                msg.timestamp + len(packages[i]) / modulator.sample_rate
+            )