autotest: add test for MAV_CMD_MISSION_START sanity checks

Tools/autotest/arducopter.py

@@ -11729,6 +11729,36 @@ def BatteryInternalUseOnly(self):
                 "id": 1
             })
 
+    def MAV_CMD_MISSION_START_p1_p2(self):
+        '''make sure we deny MAV_CMD_MISSION_START if either p1 or p2 non-zero'''
+        self.upload_simple_relhome_mission([
+            (mavutil.mavlink.MAV_CMD_NAV_TAKEOFF, 0, 0, 20),
+        ])
+        self.set_parameters({
+            "AUTO_OPTIONS": 3,
+        })
+        self.change_mode('AUTO')
+        self.wait_ready_to_arm()
+
+        self.run_cmd(
+            mavutil.mavlink.MAV_CMD_MISSION_START,
+            p1=1,
+            want_result=mavutil.mavlink.MAV_RESULT_DENIED,
+        )
+
+        self.run_cmd(
+            mavutil.mavlink.MAV_CMD_MISSION_START,
+            p2=1,
+            want_result=mavutil.mavlink.MAV_RESULT_DENIED,
+        )
+
+        self.run_cmd(
+            mavutil.mavlink.MAV_CMD_MISSION_START,
+            p1=1,
+            p2=1,
+            want_result=mavutil.mavlink.MAV_RESULT_DENIED,
+        )
+
     def tests2b(self):  # this block currently around 9.5mins here
         '''return list of all tests'''
         ret = ([
@@ -11828,6 +11858,7 @@ def tests2b(self):  # this block currently around 9.5mins here
             self.LoggingFormat,
             self.MissionRTLYawBehaviour,
             self.BatteryInternalUseOnly,
+            self.MAV_CMD_MISSION_START_p1_p2,
         ])
         return ret