Fix trailing whitespace in test docstrings and comments

Signed-off-by: xyuzh <xinyzng@gmail.com>

Author: xyuzh

python/ray/data/tests/test_download_expression.py

@@ -296,22 +296,24 @@ def test_download_expression_with_null_uris(self):
 
     def test_download_expression_with_invalid_uris(self, tmp_path):
         """Test download expression with URIs that fail to download.
-        
-        This tests the exception handling in load_uri_bytes (commit c9d91080fb)
+
+        This tests the exception handling in load_uri_bytes
         where OSError is caught and None is returned for failed downloads.
         """
         # Create one valid file
         valid_file = tmp_path / "valid.txt"
         valid_file.write_bytes(b"valid content")
-        
+
         # Create URIs: one valid, one non-existent file, one invalid path
         table = pa.Table.from_arrays(
             [
-                pa.array([
-                    f"local://{valid_file}",
-                    f"local://{tmp_path}/nonexistent.txt",  # File doesn't exist
-                    "local:///this/path/does/not/exist/file.txt",  # Invalid path
-                ]),
+                pa.array(
+                    [
+                        f"local://{valid_file}",
+                        f"local://{tmp_path}/nonexistent.txt",  # File doesn't exist
+                        "local:///this/path/does/not/exist/file.txt",  # Invalid path
+                    ]
+                ),
             ],
             names=["uri"],
         )
@@ -322,28 +324,26 @@ def test_download_expression_with_invalid_uris(self, tmp_path):
         # Should not crash - failed downloads return None
         results = ds_with_downloads.take_all()
         assert len(results) == 3
-        
+
         # First URI should succeed
         assert results[0]["bytes"] == b"valid content"
-        
+
         # Second and third URIs should fail gracefully (return None)
         assert results[1]["bytes"] is None
         assert results[2]["bytes"] is None
 
     def test_download_expression_all_size_estimations_fail(self):
         """Test download expression when all URI size estimations fail.
-        
-        This tests the divide-by-zero fix (commit 095973428f) where failed
-        size estimations append 0 instead of being skipped, and avg_nbytes_per_row == 0
-        is checked to prevent division by zero.
+
+        This tests the failed download does not cause division by zero error.
         """
         # Create URIs that will fail size estimation (non-existent files)
         # Using enough URIs to trigger size estimation sampling
         invalid_uris = [
-            f"local:///nonexistent/path/file_{i}.txt" 
+            f"local:///nonexistent/path/file_{i}.txt"
             for i in range(30)  # More than INIT_SAMPLE_BATCH_SIZE (25)
         ]
-        
+
         table = pa.Table.from_arrays(
             [pa.array(invalid_uris)],
             names=["uri"],
@@ -356,15 +356,17 @@ def test_download_expression_all_size_estimations_fail(self):
         # The PartitionActor should handle all failed size estimations gracefully
         # and fall back to using the number of rows in the block as partition size
         results = ds_with_downloads.take_all()
-        
+
         # All downloads should fail gracefully (return None)
         assert len(results) == 30
         for result in results:
             assert result["bytes"] is None
 
-    def test_download_expression_mixed_valid_and_invalid_size_estimation(self, tmp_path):
+    def test_download_expression_mixed_valid_and_invalid_size_estimation(
+        self, tmp_path
+    ):
         """Test download expression with mix of valid and invalid URIs for size estimation.
-        
+
         This tests that size estimation handles partial failures correctly.
         """
         # Create some valid files
@@ -373,7 +375,7 @@ def test_download_expression_mixed_valid_and_invalid_size_estimation(self, tmp_p
             file_path = tmp_path / f"valid_{i}.txt"
             file_path.write_bytes(b"x" * 100)  # 100 bytes each
             valid_files.append(str(file_path))
-        
+
         # Mix valid and invalid URIs
         mixed_uris = []
         for i in range(30):
@@ -383,7 +385,7 @@ def test_download_expression_mixed_valid_and_invalid_size_estimation(self, tmp_p
             else:
                 # Others are invalid
                 mixed_uris.append(f"local:///nonexistent/file_{i}.txt")
-        
+
         table = pa.Table.from_arrays(
             [pa.array(mixed_uris)],
             names=["uri"],
@@ -395,7 +397,7 @@ def test_download_expression_mixed_valid_and_invalid_size_estimation(self, tmp_p
         # Should not crash - should handle mixed valid/invalid gracefully
         results = ds_with_downloads.take_all()
         assert len(results) == 30
-        
+
         # Verify valid URIs downloaded successfully
         for i, result in enumerate(results):
             if i % 3 == 0 and i // 3 < len(valid_files):