added black box tests and bug fixes

fancy_gym/utils/make_env_helpers.py

@@ -166,6 +166,15 @@ def make_bb(
         # We have to learn the length when learning sub_trajectories trajectories
         phase_kwargs['learn_tau'] = True
 
+    # set tau bounds to minimum of two env steps otherwise computing the velocity is not possible.
+    # maximum is full duration of one episode.
+    if phase_kwargs.get('learn_tau'):
+        phase_kwargs["tau_bound"] = [env.dt * 2, black_box_kwargs['duration']]
+
+    # Max delay is full duration minus two steps due to above reason
+    if phase_kwargs.get('learn_delay'):
+        phase_kwargs["delay_bound"] = [0, black_box_kwargs['duration'] - env.dt * 2]
+
     phase_gen = get_phase_generator(**phase_kwargs)
     basis_gen = get_basis_generator(phase_generator=phase_gen, **basis_kwargs)
     controller = get_controller(**controller_kwargs)