Mark pipeline tests to skip them easily (#21887)

* Mark pipeline tests to skip them easily

* Mark the mixin as pipeline test

* Update src/transformers/testing_utils.py

Co-authored-by: Yih-Dar <2521628+ydshieh@users.noreply.github.com>

---------

Co-authored-by: Yih-Dar <2521628+ydshieh@users.noreply.github.com>

src/transformers/testing_utils.py

@@ -145,6 +145,7 @@ _run_custom_tokenizers = parse_flag_from_env("RUN_CUSTOM_TOKENIZERS", default=Fa
 _run_staging = parse_flag_from_env("HUGGINGFACE_CO_STAGING", default=False)
 _run_git_lfs_tests = parse_flag_from_env("RUN_GIT_LFS_TESTS", default=False)
 _tf_gpu_memory_limit = parse_int_from_env("TF_GPU_MEMORY_LIMIT", default=None)
+_run_pipeline_tests = parse_flag_from_env("RUN_PIPELINE_TESTS", default=True)
 
 
 def is_pt_tf_cross_test(test_case):
@@ -202,6 +203,22 @@ def is_staging_test(test_case):
             return pytest.mark.is_staging_test()(test_case)
 
 
+def is_pipeline_test(test_case):
+    """
+    Decorator marking a test as a pipeline test. If RUN_PIPELINE_TESTS is set to a falsy value, those tests will be
+    skipped.
+    """
+    if not _run_pipeline_tests:
+        return unittest.skip("test is pipeline test")(test_case)
+    else:
+        try:
+            import pytest  # We don't need a hard dependency on pytest in the main library
+        except ImportError:
+            return test_case
+        else:
+            return pytest.mark.is_pipeline_test()(test_case)
+
+
 def slow(test_case):
     """
     Decorator marking a test as slow.