diff --git a/flatland/envs/generators.py b/flatland/envs/generators.py
index c6b4b5a79182617366d89373867058a70a9e398d..ec579c1dbd080dc53504421e6a58673e205f6725 100644
--- a/flatland/envs/generators.py
+++ b/flatland/envs/generators.py
@@ -232,7 +232,7 @@ def rail_from_file(filename):
     return generator
 
 
-def rail_from_GridTransitionMap_generator(rail_map):
+def rail_from_grid_transition_map(rail_map):
     """
     Utility to convert a rail given by a GridTransitionMap map with the correct
     16-bit transitions specifications.
diff --git a/flatland/envs/rail_env.py b/flatland/envs/rail_env.py
index 34762c0bb1d4de1cb82ee82e139113977b7e7a7d..996301a84f06f185ba9ed605ea1145f404c8b16e 100644
--- a/flatland/envs/rail_env.py
+++ b/flatland/envs/rail_env.py
@@ -93,7 +93,7 @@ class RailEnv(Environment):
             starting positions, targets, and initial orientations for agent handle.
             Implemented functions are:
                 random_rail_generator : generate a random rail of given size
-                rail_from_GridTransitionMap_generator(rail_map) : generate a rail from
+                rail_from_grid_transition_map(rail_map) : generate a rail from
                                         a GridTransitionMap object
                 rail_from_manual_sp ecifications_generator(rail_spec) : generate a rail from
                                         a rail specifications array
diff --git a/tests/test_distance_map.py b/tests/test_distance_map.py
index 742e841c1a699f849a19c1f27f1b084b440a155a..12e0c092a37a475ab6e7dde21c665778e06f5e59 100644
--- a/tests/test_distance_map.py
+++ b/tests/test_distance_map.py
@@ -2,7 +2,7 @@ import numpy as np
 
 from flatland.core.grid.grid4 import Grid4Transitions
 from flatland.core.transition_map import GridTransitionMap
-from flatland.envs.generators import rail_from_GridTransitionMap_generator
+from flatland.envs.generators import rail_from_grid_transition_map
 from flatland.envs.observations import TreeObsForRailEnv
 from flatland.envs.predictions import ShortestPathPredictorForRailEnv
 from flatland.envs.rail_env import RailEnv
@@ -33,7 +33,7 @@ def test_walker():
     rail.grid = rail_map
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=1,
                   obs_builder_object=TreeObsForRailEnv(max_depth=2,
                                                        predictor=ShortestPathPredictorForRailEnv(max_depth=10)),
diff --git a/tests/test_flatland_envs_observations.py b/tests/test_flatland_envs_observations.py
index d400dc226a71e1a9c185012fccae3c852bcd42aa..c2252619957d42a9e60831f23522b5018ee60e8b 100644
--- a/tests/test_flatland_envs_observations.py
+++ b/tests/test_flatland_envs_observations.py
@@ -5,7 +5,7 @@ import numpy as np
 
 from flatland.core.grid.grid4 import Grid4TransitionsEnum
 from flatland.envs.agent_utils import EnvAgent
-from flatland.envs.generators import rail_from_GridTransitionMap_generator
+from flatland.envs.generators import rail_from_grid_transition_map
 from flatland.envs.observations import GlobalObsForRailEnv, TreeObsForRailEnv
 from flatland.envs.predictions import ShortestPathPredictorForRailEnv
 from flatland.envs.rail_env import RailEnv, RailEnvActions
@@ -20,7 +20,7 @@ def test_global_obs():
 
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=1,
                   obs_builder_object=GlobalObsForRailEnv())
 
@@ -89,7 +89,7 @@ def test_reward_function_conflict(rendering=False):
     rail, rail_map = make_simple_rail()
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=2,
                   obs_builder_object=TreeObsForRailEnv(max_depth=2, predictor=ShortestPathPredictorForRailEnv()),
                   )
@@ -167,7 +167,7 @@ def test_reward_function_waiting(rendering=False):
     rail, rail_map = make_simple_rail()
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=2,
                   obs_builder_object=TreeObsForRailEnv(max_depth=2, predictor=ShortestPathPredictorForRailEnv()),
                   )
diff --git a/tests/test_flatland_envs_predictions.py b/tests/test_flatland_envs_predictions.py
index c90f91a041b16cee2dc55a58562d34a0b9100560..eec939e23e6fe4235f3e2831040e87181b9bc778 100644
--- a/tests/test_flatland_envs_predictions.py
+++ b/tests/test_flatland_envs_predictions.py
@@ -5,7 +5,7 @@ import pprint
 import numpy as np
 
 from flatland.core.grid.grid4 import Grid4TransitionsEnum
-from flatland.envs.generators import rail_from_GridTransitionMap_generator
+from flatland.envs.generators import rail_from_grid_transition_map
 from flatland.envs.observations import TreeObsForRailEnv
 from flatland.envs.predictions import DummyPredictorForRailEnv, ShortestPathPredictorForRailEnv
 from flatland.envs.rail_env import RailEnv
@@ -20,7 +20,7 @@ def test_dummy_predictor(rendering=False):
 
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=1,
                   obs_builder_object=TreeObsForRailEnv(max_depth=2, predictor=DummyPredictorForRailEnv(max_depth=10)),
                   )
@@ -110,7 +110,7 @@ def test_shortest_path_predictor(rendering=False):
     rail, rail_map = make_simple_rail()
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=1,
                   obs_builder_object=TreeObsForRailEnv(max_depth=2, predictor=ShortestPathPredictorForRailEnv()),
                   )
@@ -229,7 +229,7 @@ def test_shortest_path_predictor_conflicts(rendering=False):
     rail, rail_map = make_simple_rail()
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=2,
                   obs_builder_object=TreeObsForRailEnv(max_depth=2, predictor=ShortestPathPredictorForRailEnv()),
                   )
diff --git a/tests/test_flatland_envs_rail_env.py b/tests/test_flatland_envs_rail_env.py
index 3a50c482176cc1352a3587edcb92704525c58c08..71dc87ceddde986be763491d28dd2b70673632f4 100644
--- a/tests/test_flatland_envs_rail_env.py
+++ b/tests/test_flatland_envs_rail_env.py
@@ -8,7 +8,7 @@ from flatland.core.transition_map import GridTransitionMap
 from flatland.envs.agent_utils import EnvAgent
 from flatland.envs.agent_utils import EnvAgentStatic
 from flatland.envs.generators import complex_rail_generator
-from flatland.envs.generators import rail_from_GridTransitionMap_generator
+from flatland.envs.generators import rail_from_grid_transition_map
 from flatland.envs.observations import GlobalObsForRailEnv
 from flatland.envs.rail_env import RailEnv
 
@@ -85,7 +85,7 @@ def test_rail_environment_single_agent():
     rail.grid = rail_map
     rail_env = RailEnv(width=3,
                        height=3,
-                       rail_generator=rail_from_GridTransitionMap_generator(rail),
+                       rail_generator=rail_from_grid_transition_map(rail),
                        number_of_agents=1,
                        obs_builder_object=GlobalObsForRailEnv())
 
@@ -164,7 +164,7 @@ def test_dead_end():
     rail.grid = rail_map
     rail_env = RailEnv(width=rail_map.shape[1],
                        height=rail_map.shape[0],
-                       rail_generator=rail_from_GridTransitionMap_generator(rail),
+                       rail_generator=rail_from_grid_transition_map(rail),
                        number_of_agents=1,
                        obs_builder_object=GlobalObsForRailEnv())
 
@@ -208,7 +208,7 @@ def test_dead_end():
     rail.grid = rail_map
     rail_env = RailEnv(width=rail_map.shape[1],
                        height=rail_map.shape[0],
-                       rail_generator=rail_from_GridTransitionMap_generator(rail),
+                       rail_generator=rail_from_grid_transition_map(rail),
                        number_of_agents=1,
                        obs_builder_object=GlobalObsForRailEnv())
 
diff --git a/tests/tests_generators.py b/tests/tests_generators.py
index 79a780db052e47d0df32a10868e6b67b51eba79e..449b83294173c9665f54c34a668579b222f0c281 100644
--- a/tests/tests_generators.py
+++ b/tests/tests_generators.py
@@ -3,7 +3,7 @@
 
 import numpy as np
 
-from flatland.envs.generators import rail_from_GridTransitionMap_generator, rail_from_file, complex_rail_generator, \
+from flatland.envs.generators import rail_from_grid_transition_map, rail_from_file, complex_rail_generator, \
     random_rail_generator, empty_rail_generator
 from flatland.envs.observations import TreeObsForRailEnv
 from flatland.envs.predictions import ShortestPathPredictorForRailEnv
@@ -30,8 +30,6 @@ def test_empty_rail_generator():
     # Check that no agents where placed
     assert env.get_num_agents() == 0
 
-    return
-
 
 def test_random_rail_generator():
     np.random.seed(0)
@@ -48,8 +46,6 @@ def test_random_rail_generator():
     assert env.rail.grid.shape == (y_dim, x_dim)
     assert env.get_num_agents() == n_agents
 
-    return
-
 
 def test_complex_rail_generator():
     n_agents = 10
@@ -65,6 +61,7 @@ def test_complex_rail_generator():
                   rail_generator=complex_rail_generator(nr_start_goal=n_start, nr_extra=0, min_dist=min_dist)
                   )
     assert env.get_num_agents() == 2
+    assert env.rail.grid.shape == (y_dim, x_dim)
 
     min_dist = 2 * x_dim
 
@@ -75,6 +72,7 @@ def test_complex_rail_generator():
                   rail_generator=complex_rail_generator(nr_start_goal=n_start, nr_extra=0, min_dist=min_dist)
                   )
     assert env.get_num_agents() == 0
+    assert env.rail.grid.shape == (y_dim, x_dim)
 
     # Check that everything stays the same when correct parameters are given
     min_dist = 2
@@ -87,15 +85,16 @@ def test_complex_rail_generator():
                   rail_generator=complex_rail_generator(nr_start_goal=n_start, nr_extra=0, min_dist=min_dist)
                   )
     assert env.get_num_agents() == n_agents
-
-    return
+    assert env.rail.grid.shape == (y_dim, x_dim)
 
 
-def test_rail_from_GridTransitionMap_generator():
+def test_rail_from_grid_transition_map():
     rail, rail_map = make_simple_rail()
+    n_agents = 3
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
+                  number_of_agents=n_agents
                   )
     nr_rail_elements = np.count_nonzero(env.rail.grid)
 
@@ -105,7 +104,8 @@ def test_rail_from_GridTransitionMap_generator():
     # Check that agents are placed on a rail
     for a in env.agents:
         assert env.rail.grid[a.position] != 0
-    return
+
+    assert env.get_num_agents() == n_agents
 
 
 def tests_rail_from_file():
@@ -113,7 +113,7 @@ def tests_rail_from_file():
     rail, rail_map = make_simple_rail()
     env = RailEnv(width=rail_map.shape[1],
                   height=rail_map.shape[0],
-                  rail_generator=rail_from_GridTransitionMap_generator(rail),
+                  rail_generator=rail_from_grid_transition_map(rail),
                   number_of_agents=3,
                   obs_builder_object=TreeObsForRailEnv(max_depth=2, predictor=ShortestPathPredictorForRailEnv()),
                   )
@@ -134,4 +134,3 @@ def tests_rail_from_file():
     assert np.all(np.array_equal(rails_initial, rails_loaded))
     assert agents_initial == agents_loaded
 
-    return