autotest: add test home is restored persistently on wdog reset

Tools/autotest/arduplane.py

@@ -9,6 +9,7 @@ AP_FLAKE8_CLEAN
 from __future__ import print_function
 import math
 import os
+import signal
 import time
 
 from pymavlink import quaternion
@@ -2992,6 +2993,59 @@ class AutoTestPlane(AutoTest):
             True,
             True)
 
+    def WatchdogHome(self):
+        if self.gdb:
+            # we end up signalling the wrong process.  I think.
+            # Probably need to have a "sitl_pid()" method to get the
+            # ardupilot process's PID.
+            self.progress("######## Skipping WatchdogHome test under GDB")
+            return
+
+        ex = None
+        try:
+            self.progress("Enabling watchdog")
+            self.set_parameter("BRD_OPTIONS", 1 << 0)
+            self.reboot_sitl()
+            self.wait_ready_to_arm()
+            self.progress("Explicitly setting home to a known location")
+            orig_home = self.poll_home_position()
+            new_home = orig_home
+            new_home.latitude = new_home.latitude + 1000
+            new_home.longitude = new_home.longitude + 2000
+            new_home.altitude = new_home.altitude + 300000 # 300 metres
+            self.run_cmd_int(
+                mavutil.mavlink.MAV_CMD_DO_SET_HOME,
+                0, # p1,
+                0, # p2,
+                0, # p3,
+                0, # p4,
+                new_home.latitude,
+                new_home.longitude,
+                new_home.altitude/1000.0, # mm => m
+            )
+            old_bootcount = self.get_parameter('STAT_BOOTCNT')
+            self.progress("Forcing watchdog reset")
+            os.kill(self.sitl.pid, signal.SIGALRM)
+            self.detect_and_handle_reboot(old_bootcount)
+            self.wait_statustext("WDG:")
+            self.wait_statustext("IMU1 is using GPS")  # won't be come armable
+            self.progress("Verifying home position")
+            post_reboot_home = self.poll_home_position()
+            delta = self.get_distance_int(new_home, post_reboot_home)
+            max_delta = 1
+            if delta > max_delta:
+                raise NotAchievedException(
+                    "New home not where it should be (dist=%f) (want=%s) (got=%s)" %
+                    (delta, str(new_home), str(post_reboot_home)))
+        except Exception as e:
+            self.print_exception_caught(e)
+            ex = e
+
+        self.reboot_sitl()
+
+        if ex is not None:
+            raise ex
+
     def tests(self):
         '''return list of all tests'''
         ret = super(AutoTestPlane, self).tests()
@@ -3125,6 +3179,10 @@ class AutoTestPlane(AutoTest):
              "Test DeepStall Landing",
              self.fly_deepstall),
 
+            ("WatchdogHome",
+             "Ensure home is restored after watchdog reset",
+             self.WatchdogHome),
+
             ("LargeMissions",
              "Test Manipulation of Large missions",
              self.test_large_missions),