fix: resolve CI/CD test failures and linting issues

tests/test_converters/test_yaml.py

@@ -3,7 +3,7 @@
 import pytest
 import tempfile
 import os
-from pathlib import Path
+import yaml
 
 from config_convert.converters import YAMLConverter
 
@@ -56,7 +56,6 @@ class TestYAMLConverter:
         assert loaded == original
 
     def test_load_file(self, converter, temp_file, sample_yaml):
-        import yaml
         gen = temp_file(sample_yaml, suffix=".yaml")
         path = next(gen)
         try:
@@ -66,8 +65,6 @@ class TestYAMLConverter:
             os.unlink(path)
 
     def test_dump_file(self, converter, temp_dir, sample_yaml):
-        import yaml
-        import shutil
         path = tempfile.mktemp(suffix=".yaml")
         try:
             data = yaml.safe_load(sample_yaml)
@@ -75,7 +72,7 @@ class TestYAMLConverter:
             result = converter.load(path)
             assert result == data
         finally:
-            if Path(path).exists():
+            if os.path.exists(path):
                 os.unlink(path)
 
     def test_invalid_yaml_raises(self, converter):