Tools: test use Location::AltFrame for guided_state.target_alt_frame

Tools/autotest/arduplane.py

@@ -5508,6 +5508,7 @@ def RunMissionScript(self):
 
     def MAV_CMD_GUIDED_CHANGE_ALTITUDE(self):
         '''test handling of MAV_CMD_GUIDED_CHANGE_ALTITUDE'''
+        self.start_subtest("set home relative altitude")
         self.takeoff(30, relative=True)
         self.change_mode('GUIDED')
         for alt in 50, 70:
@@ -5519,6 +5520,7 @@ def MAV_CMD_GUIDED_CHANGE_ALTITUDE(self):
             self.wait_altitude(alt-1, alt+1, timeout=30, relative=True)
 
         # test for #24535
+        self.start_subtest("switch to loiter and resume maintains altitude")
         self.change_mode('LOITER')
         self.delay_sim_time(5)
         self.change_mode('GUIDED')
@@ -5529,6 +5531,26 @@ def MAV_CMD_GUIDED_CHANGE_ALTITUDE(self):
             timeout=30,
             relative=True,
         )
+        # test that this works if switching between RELATIVE (HOME) and GLOBAL(AMSL)
+        self.start_subtest("set global/AMSL altitude switch to loiter and resume")
+        alt = 650
+        self.run_cmd_int(
+            mavutil.mavlink.MAV_CMD_GUIDED_CHANGE_ALTITUDE,
+            p7=alt,
+            frame=mavutil.mavlink.MAV_FRAME_GLOBAL,
+        )
+        self.wait_altitude(alt-1, alt+1, timeout=30, relative=False)
+        self.change_mode('LOITER')
+        self.delay_sim_time(5)
+        self.change_mode('GUIDED')
+        self.wait_altitude(
+            alt-3,  # NOTE: reuse of alt from above CHANGE_ALTITUDE
+            alt+3,
+            minimum_duration=10,
+            timeout=30,
+            relative=False,
+        )
+        self.delay_sim_time(5)
         self.fly_home_land_and_disarm()
 
     def _MAV_CMD_PREFLIGHT_CALIBRATION(self, command):