Introducing malfunction_generators

This resolves issue #273

fixed tests

tests/test_global_observation.py

 import numpy as np
 
 from flatland.envs.agent_utils import EnvAgent, RailAgentStatus
+from flatland.envs.malfunction_generators import malfunction_from_params
 from flatland.envs.observations import GlobalObsForRailEnv
 from flatland.envs.rail_env import RailEnv, RailEnvActions
 from flatland.envs.rail_generators import sparse_rail_generator
@@ -28,7 +29,7 @@ def test_get_global_observation():
                                                                             grid_mode=False
                                                                             ),
                   schedule_generator=sparse_schedule_generator(speed_ration_map), number_of_agents=number_of_agents,
-                  obs_builder_object=GlobalObsForRailEnv(), malfunction_generator=stochastic_data)
+                  obs_builder_object=GlobalObsForRailEnv(), malfunction_generator=malfunction_from_params(stochastic_data))
     env.reset()
 
     obs, all_rewards, done, _ = env.step({i: RailEnvActions.MOVE_FORWARD for i in range(number_of_agents)})

tests/test_random_seeding.py

 import numpy as np
 
+from flatland.envs.malfunction_generators import malfunction_from_params
 from flatland.envs.observations import GlobalObsForRailEnv, TreeObsForRailEnv
 from flatland.envs.predictions import ShortestPathPredictorForRailEnv
 from flatland.envs.rail_env import RailEnv
@@ -108,12 +109,12 @@ def test_seeding_and_malfunction():
     for tests in range(1, 100):
         env = RailEnv(width=25, height=30, rail_generator=rail_from_grid_transition_map(rail),
                       schedule_generator=random_schedule_generator(), number_of_agents=10,
-                      obs_builder_object=GlobalObsForRailEnv(), malfunction_generator=stochastic_data)
+                      obs_builder_object=GlobalObsForRailEnv(), malfunction_generator=malfunction_from_params(stochastic_data))
 
         # Tree Observation
         env2 = RailEnv(width=25, height=30, rail_generator=rail_from_grid_transition_map(rail),
                        schedule_generator=random_schedule_generator(), number_of_agents=10,
-                       obs_builder_object=GlobalObsForRailEnv(), malfunction_generator=stochastic_data)
+                       obs_builder_object=GlobalObsForRailEnv(), malfunction_generator=malfunction_from_params(stochastic_data))
 
         env.reset(True, False, True, random_seed=tests)
         env2.reset(True, False, True, random_seed=tests)