[testing] skip decorators: docs, tests, bugs (#7334)

* skip decorators: docs, tests, bugs

* another important note

* style

* bloody style

* add @pytest.mark.parametrize

* add note

* no idea what it wants :(

src/transformers/testing_utils.py

@@ -62,8 +62,9 @@ def slow(test_case):
 
     """
     if not _run_slow_tests:
-        test_case = unittest.skip("test is slow")(test_case)
-    return test_case
+        return unittest.skip("test is slow")(test_case)
+    else:
+        return test_case
 
 
 def custom_tokenizers(test_case):
@@ -75,8 +76,9 @@ def custom_tokenizers(test_case):
     to a truthy value to run them.
     """
     if not _run_custom_tokenizers:
-        test_case = unittest.skip("test of custom tokenizers")(test_case)
-    return test_case
+        return unittest.skip("test of custom tokenizers")(test_case)
+    else:
+        return test_case
 
 
 def require_torch(test_case):
@@ -87,8 +89,9 @@ def require_torch(test_case):
 
     """
     if not _torch_available:
-        test_case = unittest.skip("test requires PyTorch")(test_case)
-    return test_case
+        return unittest.skip("test requires PyTorch")(test_case)
+    else:
+        return test_case
 
 
 def require_tf(test_case):
@@ -99,8 +102,9 @@ def require_tf(test_case):
 
     """
     if not _tf_available:
-        test_case = unittest.skip("test requires TensorFlow")(test_case)
-    return test_case
+        return unittest.skip("test requires TensorFlow")(test_case)
+    else:
+        return test_case
 
 
 def require_multigpu(test_case):
@@ -119,7 +123,8 @@ def require_multigpu(test_case):
 
     if torch.cuda.device_count() < 2:
         return unittest.skip("test requires multiple GPUs")(test_case)
-    return test_case
+    else:
+        return test_case
 
 
 def require_non_multigpu(test_case):
@@ -133,7 +138,8 @@ def require_non_multigpu(test_case):
 
     if torch.cuda.device_count() > 1:
         return unittest.skip("test requires 0 or 1 GPU")(test_case)
-    return test_case
+    else:
+        return test_case
 
 
 def require_torch_tpu(test_case):
@@ -142,8 +148,8 @@ def require_torch_tpu(test_case):
     """
     if not _torch_tpu_available:
         return unittest.skip("test requires PyTorch TPU")
-
-    return test_case
+    else:
+        return test_case
 
 
 if _torch_available:
@@ -154,9 +160,9 @@ else:
 
 
 def require_torch_and_cuda(test_case):
-    """Decorator marking a test that requires CUDA and PyTorch). """
+    """Decorator marking a test that requires CUDA and PyTorch. """
     if torch_device != "cuda":
-        return unittest.skip("test requires CUDA")
+        return unittest.skip("test requires CUDA")(test_case)
     else:
         return test_case
 
@@ -165,15 +171,17 @@ def require_datasets(test_case):
     """Decorator marking a test that requires datasets."""
 
     if not _datasets_available:
-        test_case = unittest.skip("test requires Datasets")(test_case)
-    return test_case
+        return unittest.skip("test requires `datasets`")(test_case)
+    else:
+        return test_case
 
 
 def require_faiss(test_case):
     """Decorator marking a test that requires faiss."""
     if not _faiss_available:
-        test_case = unittest.skip("test requires Faiss")(test_case)
-    return test_case
+        return unittest.skip("test requires `faiss`")(test_case)
+    else:
+        return test_case
 
 
 def get_tests_dir():