Fix bugs in 0.2 (#344)

* Fix some bugs

tests/test_solvers/test_supervised_solver.py

@@ -5,7 +5,7 @@ from pina import Condition, LabelTensor
 from pina.solvers import SupervisedSolver
 from pina.trainer import Trainer
 from pina.model import FeedForward
-from pina.loss.loss_interface import LpLoss
+from pina.loss import LpLoss
 
 
 class NeuralOperatorProblem(AbstractProblem):
@@ -94,11 +94,9 @@ class GraphModel(torch.nn.Module):
         return x
 
 def test_graph():
-
     solver = AutoSolver(problem = problem, model=GraphModel(2, 1), loss=LpLoss())
     trainer = Trainer(solver=solver, max_epochs=30, accelerator='cpu', batch_size=20)
     trainer.train()
-    assert False
 
 
 def test_train_cpu():
@@ -107,6 +105,7 @@ def test_train_cpu():
     trainer.train()
 
 
+
 # def test_train_restore():
 #     tmpdir = "tests/tmp_restore"
 #     solver = SupervisedSolver(problem=problem,
@@ -153,4 +152,4 @@ def test_train_cpu():
 #                 model=model_extra_feats,
 #                 extra_features=extra_feats)
 #     trainer = Trainer(solver=pinn, max_epochs=5, accelerator='cpu')
-#     trainer.train()
+#     trainer.train()