[testing] a new TestCasePlus subclass + get_auto_remove_tmp_dir() (#6494)

* [testing] switch to a new TestCasePlus + get_auto_remove_tmp_dir() for auto-removal of tmp dirs

* respect after=True for tempfile, simplify code

* comments

* comment fix

* put `before` last in args, so can make debug even faster

examples/bert-loses-patience/test_run_glue_with_pabee.py

@@ -1,11 +1,10 @@
 import argparse
 import logging
-import shutil
 import sys
-import unittest
 from unittest.mock import patch
 
 import run_glue_with_pabee
+from transformers.testing_utils import TestCasePlus
 
 
 logging.basicConfig(level=logging.DEBUG)
@@ -20,20 +19,19 @@ def get_setup_file():
     return args.f
 
 
-def clean_test_dir(path):
-    shutil.rmtree(path, ignore_errors=True)
-
-
-class PabeeTests(unittest.TestCase):
+class PabeeTests(TestCasePlus):
     def test_run_glue(self):
         stream_handler = logging.StreamHandler(sys.stdout)
         logger.addHandler(stream_handler)
 
-        testargs = """
+        tmp_dir = self.get_auto_remove_tmp_dir()
+        testargs = f"""
             run_glue_with_pabee.py
             --model_type albert
             --model_name_or_path albert-base-v2
             --data_dir ./tests/fixtures/tests_samples/MRPC/
+            --output_dir {tmp_dir}
+            --overwrite_output_dir
             --task_name mrpc
             --do_train
             --do_eval
@@ -42,16 +40,11 @@ class PabeeTests(unittest.TestCase):
             --learning_rate=2e-5
             --max_steps=50
             --warmup_steps=2
-            --overwrite_output_dir
             --seed=42
             --max_seq_length=128
-            """
-        output_dir = "./tests/fixtures/tests_samples/temp_dir_{}".format(hash(testargs))
-        testargs += "--output_dir " + output_dir
-        testargs = testargs.split()
+            """.split()
+
         with patch.object(sys, "argv", testargs):
             result = run_glue_with_pabee.main()
             for value in result.values():
                 self.assertGreaterEqual(value, 0.75)
-
-        clean_test_dir(output_dir)