Tools: autotest for takeoff altitude

Tools/autotest/ArduCopter_Tests/TakeoffAlt/copter_takeoff.txt

@@ -0,0 +1,4 @@
+QGC WPL 110
+0	1	0	16	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.000000	1
+1	0	3	22	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	-10.000000	1
+2	0	3	16	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.00000000	0.000000	1

Tools/autotest/arducopter.py

@@ -2347,6 +2347,52 @@ class AutoTestCopter(AutoTest):
         self.context_pop()
         self.fly_auto_test()
 
+    # test takeoff altitude
+    def test_takeoff_alt(self):
+        # Test case #1 (set target altitude to relative -10m from the ground, -10m is invalid, so it is set to 1m)
+        self.progress("Testing relative alt from the ground")
+        self.do_takeoff_alt("copter_takeoff.txt", 1, False)
+        # Test case #2 (set target altitude to relative -10m during flight, -10m is invalid, so keeps current altitude)
+        self.progress("Testing relative alt during flight")
+        self.do_takeoff_alt("copter_takeoff.txt", 10, True)
+
+        self.progress("Takeoff mission completed: passed!")
+
+    def do_takeoff_alt(self, mission_file, target_alt, during_flight=False):
+        self.progress("# Load %s" % mission_file)
+        # load the waypoint count
+        num_wp = self.load_mission(mission_file, strict=False)
+        if not num_wp:
+            raise NotAchievedException("load %s failed" % mission_file)
+
+        self.set_current_waypoint(1)
+
+        self.change_mode("GUIDED")
+        self.wait_ready_to_arm()
+        self.arm_vehicle()
+
+        if during_flight:
+            self.user_takeoff(alt_min=target_alt)
+
+        # switch into AUTO mode and raise throttle
+        self.change_mode("AUTO")
+        self.set_rc(3, 1500)
+
+        # fly the mission
+        self.wait_waypoint(0, num_wp-1, timeout=500)
+
+        # altitude check
+        self.wait_altitude(target_alt - 1 , target_alt + 1, relative=True)
+
+        self.change_mode('LAND')
+
+        # set throttle to minimum
+        self.zero_throttle()
+
+        # wait for disarm
+        self.wait_disarmed()
+        self.progress("MOTORS DISARMED OK")
+
     def fly_motor_fail(self, fail_servo=0, fail_mul=0.0, holdtime=30):
         """Test flight with reduced motor efficiency"""
 
@@ -8118,6 +8164,10 @@ class AutoTestCopter(AutoTest):
              "Fly copter mission",
              self.fly_auto_test),  # 37s
 
+            ("TakeoffAlt",
+             "Test Takeoff command altitude",
+             self.test_takeoff_alt), # 12s
+
             ("SplineLastWaypoint",
              "Test Spline as last waypoint",
              self.test_spline_last_waypoint),