message: update test including essential parts
diff: @@ -232,12 +232,20 @@ def wasserstein_distance(X, Y, matching=False, order=1., internal_p=np.inf, enab
  if not matching:
  return _perstot(Y, order, internal_p, enable_autodiff)
  else:
  - return _perstot(Y, order, internal_p, enable_autodiff), np.array([[-1, j] for j in range(m)])
  + cost = _perstot(Y, order, internal_p, enable_autodiff)
  + if cost == np.inf: # We had some essential part here.
  + return cost, None
  + else:
  + return cost, np.array([[-1, j] for j in range(m)])
  elif m == 0:
  if not matching:
  return _perstot(X, order, internal_p, enable_autodiff)
  else:
  - return _perstot(X, order, internal_p, enable_autodiff), np.array([[i, -1] for i in range(n)])
  + cost = _perstot(X, order, internal_p, enable_autodiff)
  + if cost == np.inf:
  + return cost, None
  + else:
  + return np.array([[i, -1] for i in range(n)])
  # Second step: handle essential parts
  