Avoid root logger's level being changed (#28638)

* avoid root logger's level being changed

---------
Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

tests/trainer/test_trainer.py

@@ -50,6 +50,7 @@ from transformers.testing_utils import (
     TOKEN,
     USER,
     CaptureLogger,
+    LoggingLevel,
     TestCasePlus,
     backend_device_count,
     execute_subprocess_async,
@@ -1290,17 +1291,19 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
         else:
             self.assertNotIn(log_info_string, cl.out)
 
-        # test with low log_level - lower than info
-        with CaptureLogger(logger) as cl:
-            trainer = get_regression_trainer(log_level="debug")
-            trainer.train()
-        self.assertIn(log_info_string, cl.out)
+        with LoggingLevel(logging.INFO):
+            # test with low log_level - lower than info
+            with CaptureLogger(logger) as cl:
+                trainer = get_regression_trainer(log_level="debug")
+                trainer.train()
+            self.assertIn(log_info_string, cl.out)
 
-        # test with high log_level - should be quiet
-        with CaptureLogger(logger) as cl:
-            trainer = get_regression_trainer(log_level="error")
-            trainer.train()
-        self.assertNotIn(log_info_string, cl.out)
+        with LoggingLevel(logging.INFO):
+            # test with high log_level - should be quiet
+            with CaptureLogger(logger) as cl:
+                trainer = get_regression_trainer(log_level="error")
+                trainer.train()
+            self.assertNotIn(log_info_string, cl.out)
 
     def test_save_checkpoints(self):
         with tempfile.TemporaryDirectory() as tmpdir: