Add ruff rule for empty line with trailing whitespace.

tests-unit/server/utils/file_operations_test.py

@@ -16,18 +16,18 @@ def temp_directory(tmp_path):
 
 def test_walk_directory(temp_directory):
     result: List[FileSystemItem] = FileSystemOperations.walk_directory(str(temp_directory))
-    
+
     assert len(result) == 5  # 2 directories and 3 files
-    
+
     files = [item for item in result if item['type'] == 'file']
     dirs = [item for item in result if item['type'] == 'directory']
-    
+
     assert len(files) == 3
     assert len(dirs) == 2
-    
+
     file_names = {file['name'] for file in files}
     assert file_names == {'file1.txt', 'file2.txt', 'file3.txt'}
-    
+
     dir_names = {dir['name'] for dir in dirs}
     assert dir_names == {'dir1', 'dir2'}