add test for landing

tests/starting_test.py

@@ -83,3 +83,13 @@ def test150from180():
 
     time_steps =_step_loop(env, 2000, time_step)
     _assert_last_time_steps(time_steps)
+
+def test_landing():
+    env = _make_env(123.46241760253906)
+    time_step = env.reset()
+
+    position = client.getMultirotorState().gps_location
+    client.moveToGPSAsync(latitude=position.latitude, longitude=position.longitude, altitude=140, velocity=10).join()
+
+    time_steps =_step_loop(env, 2000, time_step)
+    _assert_last_time_steps(time_steps)