Fix GPU test skip logic (#516)

test/test_functional_filtering.py

@@ -33,12 +33,9 @@ class TestFunctionalFiltering(unittest.TestCase):
     def test_lfilter_basic_double(self):
         self._test_lfilter_basic(torch.float64, torch.device("cpu"))
 
+    @unittest.skipIf(not torch.cuda.is_available(), "CUDA not available")
     def test_lfilter_basic_gpu(self):
-        if torch.cuda.is_available():
-            self._test_lfilter_basic(torch.float32, torch.device("cuda:0"))
-        else:
-            print("skipping GPU test for lfilter_basic because device not available")
-            pass
+        self._test_lfilter_basic(torch.float32, torch.device("cuda:0"))
 
     def _test_lfilter(self, waveform, device):
         """
@@ -87,16 +84,13 @@ class TestFunctionalFiltering(unittest.TestCase):
 
         self._test_lfilter(waveform, torch.device("cpu"))
 
+    @unittest.skipIf(not torch.cuda.is_available(), "CUDA not available")
     def test_lfilter_gpu(self):
-        if torch.cuda.is_available():
-            filepath = os.path.join(self.test_dirpath, "assets", "whitenoise.wav")
-            waveform, _ = torchaudio.load(filepath, normalization=True)
-            cuda0 = torch.device("cuda:0")
-            cuda_waveform = waveform.cuda(device=cuda0)
-            self._test_lfilter(cuda_waveform, cuda0)
-        else:
-            print("skipping GPU test for lfilter because device not available")
-            pass
+        filepath = os.path.join(self.test_dirpath, "assets", "whitenoise.wav")
+        waveform, _ = torchaudio.load(filepath, normalization=True)
+        cuda0 = torch.device("cuda:0")
+        cuda_waveform = waveform.cuda(device=cuda0)
+        self._test_lfilter(cuda_waveform, cuda0)
 
     @unittest.skipIf("sox" not in BACKENDS, "sox not available")
     @AudioBackendScope("sox")