autotest: add method to create simple relative-to-home mission

Tools/autotest/arducopter.py

@@ -6643,6 +6643,48 @@ class AutoTestCopter(AutoTest):
             self.takeoff(10)
             self.do_RTL()
 
+    def create_simple_relhome_mission(self, items_in, target_system=1, target_component=1):
+        '''takes a list of (type, n, e, alt) items.  Creates a mission in
+        absolute frame using alt as relative-to-home and n and e as
+        offsets in metres from home'''
+
+        # add a dummy waypoint for home
+        items = [(mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0)]
+        items.extend(items_in)
+        seq = 0
+        ret = []
+        for (t, n, e, alt) in items:
+            lat = 0
+            lng = 0
+            if n != 0 or e != 0:
+                loc = self.home_relative_loc_ne(n, e)
+                lat = loc.lat
+                lng = loc.lng
+            p1 = 0
+            frame = mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT_INT
+            if not self.ardupilot_stores_frame_for_cmd(t):
+                frame = mavutil.mavlink.MAV_FRAME_GLOBAL
+            ret.append(self.mav.mav.mission_item_int_encode(
+                target_system,
+                target_component,
+                seq, # seq
+                frame,
+                t,
+                0, # current
+                0, # autocontinue
+                p1, # p1
+                0, # p2
+                0, # p3
+                0, # p4
+                int(lat*1e7), # latitude
+                int(lng*1e7), # longitude
+                alt, # altitude
+                mavutil.mavlink.MAV_MISSION_TYPE_MISSION),
+            )
+            seq += 1
+
+        return ret
+
     def test_replay(self):
         '''test replay correctness'''
         self.progress("Building Replay")