test for dead ends

tests/test_environments.py

@@ -34,7 +34,6 @@ def test_rail_environment_single_agent():
     # Simple turn not in the base transitions ?
     south_east_turn = int('0100000000000010', 2)
     south_west_turn = transitions.rotate_transition(south_east_turn, 90)
-    # print(bytes(south_west_turn))
     north_east_turn = transitions.rotate_transition(south_east_turn, 270)
     north_west_turn = transitions.rotate_transition(south_east_turn, 180)
 
@@ -77,7 +76,7 @@ def test_rail_environment_single_agent():
                 valid_active_actions_done += 1
 
         # After 6 movements on this railway network, the train should be back
-        # to its original position.
+        # to its original height on the map.
         assert(initial_pos[0] == rail_env.agents_position[0][0])
 
         # We check that the train always attains its target after some time
@@ -92,3 +91,97 @@ def test_rail_environment_single_agent():
                 _, _, dones, _ = rail_env.step({0: action})
 
                 done = dones['__all__']
+
+
+def test_dead_end():
+
+    transitions = Grid4Transitions([])
+
+    straight_vertical = int('1000000000100000', 2)  # Case 1 - straight
+    straight_horizontal = transitions.rotate_transition(straight_vertical,
+                                                        90)
+
+    dead_end_from_south = int('0010000000000000', 2)  # Case 7 - dead end
+
+    # We instantiate the following railway
+    # O->-- where > is the train and O the target. After 6 steps,
+    # the train should be done.
+
+    rail_map = np.array(
+        [[transitions.rotate_transition(dead_end_from_south, 270)] +
+         [straight_horizontal] * 3 +
+         [transitions.rotate_transition(dead_end_from_south, 90)]],
+        dtype=np.uint16)
+
+    rail = GridTransitionMap(width=rail_map.shape[1],
+                             height=rail_map.shape[0],
+                             transitions=transitions)
+
+    rail.grid = rail_map
+    rail_env = RailEnv(rail, number_of_agents=1)
+
+    def check_consistency(rail_env):
+        # We run step to check that trains do not move anymore
+        # after being done.
+        for i in range(7):
+            prev_pos = rail_env.agents_position[0]
+
+            # The train cannot turn, so we check that when it tries,
+            # it stays where it is.
+            _ = rail_env.step({0: 1})
+            _ = rail_env.step({0: 3})
+            assert (rail_env.agents_position[0] == prev_pos)
+
+            _, _, dones, _ = rail_env.step({0: 2})
+
+            if i < 5:
+                assert (not dones[0] and not dones['__all__'])
+            else:
+                assert (dones[0] and dones['__all__'])
+
+    # We try the configuration in the 4 directions:
+    rail_env.reset()
+    rail_env.agents_target[0] = [0, 0]
+    rail_env.agents_position[0] = [0, 2]
+    rail_env.agents_direction[0] = 1
+    check_consistency(rail_env)
+
+    rail_env.reset()
+    rail_env.agents_target[0] = [0, 4]
+    rail_env.agents_position[0] = [0, 2]
+    rail_env.agents_direction[0] = 3
+    check_consistency(rail_env)
+
+    # In the vertical configuration:
+
+    rail_map = np.array(
+        [[dead_end_from_south]] + [[straight_vertical]] * 3 +
+        [[transitions.rotate_transition(dead_end_from_south, 180)]],
+        dtype=np.uint16)
+
+    rail = GridTransitionMap(width=rail_map.shape[1],
+                             height=rail_map.shape[0],
+                             transitions=transitions)
+
+    rail.grid = rail_map
+    rail_env = RailEnv(rail, number_of_agents=1)
+
+    rail_env.reset()
+    rail_env.agents_target[0] = [0, 0]
+    rail_env.agents_position[0] = [2, 0]
+    rail_env.agents_direction[0] = 2
+    check_consistency(rail_env)
+
+    rail_env.reset()
+    rail_env.agents_target[0] = [4, 0]
+    rail_env.agents_position[0] = [2, 0]
+    rail_env.agents_direction[0] = 0
+    check_consistency(rail_env)
+
+
+
+
+
+
+test_dead_end()
+