autotest: add do_timesync_roundtrip to do a timesync against SITL

On the assumption that ArduPilot processes mavlink packets
synchronously (or at least in order), after we have run a timesync
roundtrip we can reasonably expect any mavlink command we have sent
prior to the roundtrip to have been processed, and we should be able to
see the results in the mavlink stream.

Tools/autotest/common.py

@@ -805,6 +805,7 @@ class AutoTest(ABC):
         if self.force_ahrs_type is not None:
             self.force_ahrs_type = int(self.force_ahrs_type)
         self.logs_dir = logs_dir
+        self.timesync_number = 137
 
     @staticmethod
     def progress(text):
@@ -1604,6 +1605,38 @@ class AutoTest(ABC):
 
         self.progress("Drained %u messages from mav (%s)" % (count, rate))
 
+    def do_timesync_roundtrip(self):
+        self.progress("Doing timesync roundtrip")
+        tstart = self.get_sim_time()
+        self.mav.mav.timesync_send(0, self.timesync_number * 1000 + self.mav.source_system)
+        while True:
+            now = self.get_sim_time_cached()
+            if now - tstart > 1:
+                raise AutoTestTimeoutException("Did not get timesync response")
+            m = self.mav.recv_match(type='TIMESYNC', blocking=True, timeout=1)
+            self.progress("Received: %s" % str(m))
+            if m is None:
+                continue
+            if m.tc1 == 0:
+                self.progress("this is a timesync request, which we don't answer")
+                continue
+            if m.ts1 % 1000 != self.mav.source_system:
+                self.progress("this isn't a response to our timesync (%s)" % (m.ts1 % 1000))
+                continue
+            if int(m.ts1 / 1000) != self.timesync_number:
+                self.progress("this isn't the one we just sent")
+                continue
+            if m.get_srcSystem() != self.mav.target_system:
+                self.progress("response from system other than our target")
+                continue
+            # no component check ATM because we send broadcast...
+#            if m.get_srcComponent() != self.mav.target_component:
+#                self.progress("response from component other than our target (got=%u want=%u)" % (m.get_srcComponent(), self.mav.target_component))
+#                continue
+            self.progress("Received TIMESYNC response after %fs" % (now - tstart))
+            self.timesync_number += 1
+            break
+
     def log_filepath(self, lognum):
         '''return filepath to lognum (where lognum comes from LOG_ENTRY'''
         log_list = sorted(self.log_list())

Tools/autotest/rover.py

@@ -704,7 +704,7 @@ Brakes have negligible effect (with=%0.2fm without=%0.2fm delta=%0.2fm)
                 65535, # chan6_raw
                 65535, # chan7_raw
                 65535) # chan8_raw
-
+            self.do_timesync_roundtrip()
             m = self.mav.recv_match(type='RC_CHANNELS', blocking=True)
             self.progress("chan3=%f want=%f" % (m.chan3_raw, normal_rc_throttle))
             if m.chan3_raw == normal_rc_throttle: