fix pytest error on non-linux system (#638)

test/continuous/test_sac_with_il.py

@@ -1,11 +1,5 @@
 import argparse
 import os
-import sys
-
-try:
-    import envpool
-except ImportError:
-    envpool = None
 
 import numpy as np
 import pytest
@@ -19,6 +13,11 @@ from tianshou.utils import TensorboardLogger
 from tianshou.utils.net.common import Net
 from tianshou.utils.net.continuous import Actor, ActorProb, Critic
 
+try:
+    import envpool
+except ImportError:
+    envpool = None
+
 
 def get_args():
     parser = argparse.ArgumentParser()
@@ -57,8 +56,9 @@ def get_args():
     return args
 
 
-@pytest.mark.skipif(sys.platform != "linux", reason="envpool only support linux now")
+@pytest.mark.skipif(envpool is None, reason="EnvPool doesn't support this platform")
 def test_sac_with_il(args=get_args()):
+    # if you want to use python vector env, please refer to other test scripts
     train_envs = env = envpool.make_gym(
         args.task, num_envs=args.training_num, seed=args.seed
     )

test/discrete/test_a2c_with_il.py

@@ -2,9 +2,9 @@ import argparse
 import os
 import pprint
 
-import envpool
 import gym
 import numpy as np
+import pytest
 import torch
 from torch.utils.tensorboard import SummaryWriter
 
@@ -15,6 +15,11 @@ from tianshou.utils import TensorboardLogger
 from tianshou.utils.net.common import ActorCritic, Net
 from tianshou.utils.net.discrete import Actor, Critic
 
+try:
+    import envpool
+except ImportError:
+    envpool = None
+
 
 def get_args():
     parser = argparse.ArgumentParser()
@@ -52,7 +57,9 @@ def get_args():
     return args
 
 
+@pytest.mark.skipif(envpool is None, reason="EnvPool doesn't support this platform")
 def test_a2c_with_il(args=get_args()):
+    # if you want to use python vector env, please refer to other test scripts
     train_envs = env = envpool.make_gym(
         args.task, num_envs=args.training_num, seed=args.seed
     )

test/modelbased/test_psrl.py

@@ -2,8 +2,8 @@ import argparse
 import os
 import pprint
 
-import envpool
 import numpy as np
+import pytest
 import torch
 from torch.utils.tensorboard import SummaryWriter
 
@@ -12,6 +12,11 @@ from tianshou.policy import PSRLPolicy
 from tianshou.trainer import onpolicy_trainer
 from tianshou.utils import LazyLogger, TensorboardLogger, WandbLogger
 
+try:
+    import envpool
+except ImportError:
+    envpool = None
+
 
 def get_args():
     parser = argparse.ArgumentParser()
@@ -40,7 +45,9 @@ def get_args():
     return parser.parse_known_args()[0]
 
 
+@pytest.mark.skipif(envpool is None, reason="EnvPool doesn't support this platform")
 def test_psrl(args=get_args()):
+    # if you want to use python vector env, please refer to other test scripts
     train_envs = env = envpool.make_gym(
         args.task, num_envs=args.training_num, seed=args.seed
     )