diff --git a/repo_to_text/__init__.py b/repo_to_text/__init__.py
index 4568cbb..c86b6ca 100644
--- a/repo_to_text/__init__.py
+++ b/repo_to_text/__init__.py
@@ -1,2 +1,4 @@
+"""This is the main package for the repo_to_text package."""
+
 __author__ = 'Kirill Markin'
 __email__ = 'markinkirill@gmail.com'
diff --git a/repo_to_text/cli/__init__.py b/repo_to_text/cli/__init__.py
index da7c121..8cad49f 100644
--- a/repo_to_text/cli/__init__.py
+++ b/repo_to_text/cli/__init__.py
@@ -1,3 +1,5 @@
+"""This module contains the CLI interface for the repo_to_text package."""
+
 from .cli import create_default_settings_file, parse_args, main
 
-__all__ = ['create_default_settings_file', 'parse_args', 'main'] 
\ No newline at end of file
+__all__ = ['create_default_settings_file', 'parse_args', 'main']
diff --git a/repo_to_text/cli/cli.py b/repo_to_text/cli/cli.py
index 286ed8c..c3b3166 100644
--- a/repo_to_text/cli/cli.py
+++ b/repo_to_text/cli/cli.py
@@ -1,3 +1,7 @@
+"""
+CLI for repo-to-text
+"""
+
 import argparse
 import textwrap
 import os
@@ -12,8 +16,11 @@ def create_default_settings_file() -> None:
     """Create a default .repo-to-text-settings.yaml file."""
     settings_file = '.repo-to-text-settings.yaml'
     if os.path.exists(settings_file):
-        raise FileExistsError(f"The settings file '{settings_file}' already exists. Please remove it or rename it if you want to create a new default settings file.")
-    
+        raise FileExistsError(
+            f"The settings file '{settings_file}' already exists. "
+            "Please remove it or rename it if you want to create a new default settings file."
+        )
+
     default_settings = textwrap.dedent("""\
         # Details: https://github.com/kirill-markin/repo-to-text
         # Syntax: gitignore rules
@@ -32,7 +39,7 @@ def create_default_settings_file() -> None:
           - "README.md"
           - "LICENSE"
     """)
-    with open('.repo-to-text-settings.yaml', 'w') as f:
+    with open('.repo-to-text-settings.yaml', 'w', encoding='utf-8') as f:
         f.write(default_settings)
     print("Default .repo-to-text-settings.yaml created.")
 
@@ -42,13 +49,25 @@ def parse_args() -> argparse.Namespace:
     Returns:
         argparse.Namespace: Parsed command line arguments
     """
-    parser = argparse.ArgumentParser(description='Convert repository structure and contents to text')
+    parser = argparse.ArgumentParser(
+        description='Convert repository structure and contents to text'
+    )
     parser.add_argument('input_dir', nargs='?', default='.', help='Directory to process')
     parser.add_argument('--debug', action='store_true', help='Enable debug logging')
     parser.add_argument('--output-dir', type=str, help='Directory to save the output file')
-    parser.add_argument('--create-settings', '--init', action='store_true', help='Create default .repo-to-text-settings.yaml file')
+    parser.add_argument(
+        '--create-settings',
+        '--init',
+        action='store_true',
+        help='Create default .repo-to-text-settings.yaml file'
+    )
     parser.add_argument('--stdout', action='store_true', help='Output to stdout instead of a file')
-    parser.add_argument('--ignore-patterns', nargs='*', help="List of files or directories to ignore in both tree and content sections. Supports wildcards (e.g., '*').")
+    parser.add_argument(
+        '--ignore-patterns',
+        nargs='*',
+        help="List of files or directories to ignore in both tree and content sections. "
+        "Supports wildcards (e.g., '*')."
+    )
     return parser.parse_args()
 
 def main() -> NoReturn:
@@ -60,7 +79,7 @@ def main() -> NoReturn:
     args = parse_args()
     setup_logging(debug=args.debug)
     logging.debug('repo-to-text script started')
-    
+
     try:
         if args.create_settings:
             create_default_settings_file()
@@ -72,9 +91,9 @@ def main() -> NoReturn:
                 to_stdout=args.stdout,
                 cli_ignore_patterns=args.ignore_patterns
             )
-        
+
         logging.debug('repo-to-text script finished')
         sys.exit(0)
-    except Exception as e:
-        logging.error(f'Error occurred: {str(e)}')
-        sys.exit(1) 
\ No newline at end of file
+    except (FileNotFoundError, FileExistsError, PermissionError, OSError) as e:
+        logging.error('Error occurred: %s', str(e))
+        sys.exit(1)
diff --git a/repo_to_text/core/core.py b/repo_to_text/core/core.py
index 003d262..9dd8958 100644
--- a/repo_to_text/core/core.py
+++ b/repo_to_text/core/core.py
@@ -1,15 +1,23 @@
+"""
+Core functionality for repo-to-text
+"""
+
 import os
 import subprocess
+from typing import Tuple, Optional, List, Dict, Any
+from datetime import datetime, timezone
 import logging
 import yaml
-from datetime import datetime, timezone
-from typing import Tuple, Optional, List
 import pathspec
 from pathspec import PathSpec
 
 from ..utils.utils import check_tree_command, is_ignored_path, remove_empty_dirs
 
-def get_tree_structure(path: str = '.', gitignore_spec: Optional[PathSpec] = None, tree_and_content_ignore_spec: Optional[PathSpec] = None) -> str:
+def get_tree_structure(
+        path: str = '.',
+        gitignore_spec: Optional[PathSpec] = None,
+        tree_and_content_ignore_spec: Optional[PathSpec] = None
+    ) -> str:
     """Generate tree structure of the directory.
     
     Args:
@@ -22,17 +30,23 @@ def get_tree_structure(path: str = '.', gitignore_spec: Optional[PathSpec] = Non
     """
     if not check_tree_command():
         return ""
-    
-    logging.debug(f'Generating tree structure for path: {path}')
-    result = subprocess.run(['tree', '-a', '-f', '--noreport', path], stdout=subprocess.PIPE)
+
+    logging.debug('Generating tree structure for path: %s', path)
+    result = subprocess.run(
+        ['tree', '-a', '-f', '--noreport', path],
+        stdout=subprocess.PIPE,
+        check=True
+    )
     tree_output = result.stdout.decode('utf-8')
-    logging.debug(f'Tree output generated:\n{tree_output}')
+    logging.debug('Tree output generated:\n%s', tree_output)
 
     if not gitignore_spec and not tree_and_content_ignore_spec:
         logging.debug('No .gitignore or ignore-tree-and-content specification found')
         return tree_output
 
-    logging.debug('Filtering tree output based on .gitignore and ignore-tree-and-content specification')
+    logging.debug(
+        'Filtering tree output based on .gitignore and ignore-tree-and-content specification'
+    )
     filtered_lines: List[str] = []
 
     for line in tree_output.splitlines():
@@ -43,7 +57,7 @@ def get_tree_structure(path: str = '.', gitignore_spec: Optional[PathSpec] = Non
             full_path = line[idx:].strip()
         else:
             continue
-        
+
         if full_path == '.':
             continue
 
@@ -52,18 +66,27 @@ def get_tree_structure(path: str = '.', gitignore_spec: Optional[PathSpec] = Non
         if os.path.isdir(full_path):
             relative_path += '/'
 
-        if not should_ignore_file(full_path, relative_path, gitignore_spec, None, tree_and_content_ignore_spec):
+        if not should_ignore_file(
+            full_path,
+            relative_path,
+            gitignore_spec,
+            None,
+            tree_and_content_ignore_spec
+        ):
             display_line = line.replace('./', '', 1)
             filtered_lines.append(display_line)
         else:
-            logging.debug(f'Ignored: {relative_path}')
+            logging.debug('Ignored: %s', relative_path)
 
     filtered_tree_output = '\n'.join(filtered_lines)
-    logging.debug(f'Filtered tree structure:\n{filtered_tree_output}')
+    logging.debug('Filtered tree structure:\n%s', filtered_tree_output)
     logging.debug('Tree structure filtering complete')
     return filtered_tree_output
 
-def load_ignore_specs(path: str = '.', cli_ignore_patterns: Optional[List[str]] = None) -> Tuple[Optional[PathSpec], Optional[PathSpec], PathSpec]:
+def load_ignore_specs(
+        path: str = '.',
+        cli_ignore_patterns: Optional[List[str]] = None
+    ) -> Tuple[Optional[PathSpec], Optional[PathSpec], PathSpec]:
     """Load ignore specifications from various sources.
     
     Args:
@@ -71,7 +94,8 @@ def load_ignore_specs(path: str = '.', cli_ignore_patterns: Optional[List[str]]
         cli_ignore_patterns: List of patterns from command line
         
     Returns:
-        Tuple[Optional[PathSpec], Optional[PathSpec], PathSpec]: Tuple of gitignore_spec, content_ignore_spec, and tree_and_content_ignore_spec
+        Tuple[Optional[PathSpec], Optional[PathSpec], PathSpec]: Tuple of gitignore_spec, 
+        content_ignore_spec, and tree_and_content_ignore_spec
     """
     gitignore_spec = None
     content_ignore_spec = None
@@ -80,14 +104,16 @@ def load_ignore_specs(path: str = '.', cli_ignore_patterns: Optional[List[str]]
 
     repo_settings_path = os.path.join(path, '.repo-to-text-settings.yaml')
     if os.path.exists(repo_settings_path):
-        logging.debug(f'Loading .repo-to-text-settings.yaml from path: {repo_settings_path}')
-        with open(repo_settings_path, 'r') as f:
-            settings = yaml.safe_load(f)
+        logging.debug('Loading .repo-to-text-settings.yaml from path: %s', repo_settings_path)
+        with open(repo_settings_path, 'r', encoding='utf-8') as f:
+            settings: Dict[str, Any] = yaml.safe_load(f)
             use_gitignore = settings.get('gitignore-import-and-ignore', True)
             if 'ignore-content' in settings:
-                content_ignore_spec = pathspec.PathSpec.from_lines('gitwildmatch', settings['ignore-content'])
+                content_ignore_spec: Optional[PathSpec] = pathspec.PathSpec.from_lines(
+                    'gitwildmatch', settings['ignore-content']
+                )
             if 'ignore-tree-and-content' in settings:
-                tree_and_content_ignore_list.extend(settings['ignore-tree-and-content'])
+                tree_and_content_ignore_list.extend(settings.get('ignore-tree-and-content', []))
 
     if cli_ignore_patterns:
         tree_and_content_ignore_list.extend(cli_ignore_patterns)
@@ -95,15 +121,22 @@ def load_ignore_specs(path: str = '.', cli_ignore_patterns: Optional[List[str]]
     if use_gitignore:
         gitignore_path = os.path.join(path, '.gitignore')
         if os.path.exists(gitignore_path):
-            logging.debug(f'Loading .gitignore from path: {gitignore_path}')
-            with open(gitignore_path, 'r') as f:
+            logging.debug('Loading .gitignore from path: %s', gitignore_path)
+            with open(gitignore_path, 'r', encoding='utf-8') as f:
                 gitignore_spec = pathspec.PathSpec.from_lines('gitwildmatch', f)
 
-    tree_and_content_ignore_spec = pathspec.PathSpec.from_lines('gitwildmatch', tree_and_content_ignore_list)
+    tree_and_content_ignore_spec = pathspec.PathSpec.from_lines(
+        'gitwildmatch', tree_and_content_ignore_list
+    )
     return gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec
 
-def should_ignore_file(file_path: str, relative_path: str, gitignore_spec: Optional[PathSpec], 
-                      content_ignore_spec: Optional[PathSpec], tree_and_content_ignore_spec: Optional[PathSpec]) -> bool:
+def should_ignore_file(
+    file_path: str,
+    relative_path: str,
+    gitignore_spec: Optional[PathSpec],
+    content_ignore_spec: Optional[PathSpec],
+    tree_and_content_ignore_spec: Optional[PathSpec]
+) -> bool:
     """Check if a file should be ignored based on various ignore specifications.
     
     Args:
@@ -126,19 +159,33 @@ def should_ignore_file(file_path: str, relative_path: str, gitignore_spec: Optio
 
     result = (
         is_ignored_path(file_path) or
-        bool(gitignore_spec and gitignore_spec.match_file(relative_path)) or
-        bool(content_ignore_spec and content_ignore_spec.match_file(relative_path)) or
-        bool(tree_and_content_ignore_spec and tree_and_content_ignore_spec.match_file(relative_path)) or
+        bool(
+            gitignore_spec and
+            gitignore_spec.match_file(relative_path)
+        ) or
+        bool(
+            content_ignore_spec and
+            content_ignore_spec.match_file(relative_path)
+        ) or
+        bool(
+            tree_and_content_ignore_spec and
+            tree_and_content_ignore_spec.match_file(relative_path)
+        ) or
         os.path.basename(file_path).startswith('repo-to-text_')
     )
 
-    logging.debug(f'Checking if file should be ignored:')
-    logging.debug(f'    file_path: {file_path}')
-    logging.debug(f'    relative_path: {relative_path}')
-    logging.debug(f'    Result: {result}')
+    logging.debug('Checking if file should be ignored:')
+    logging.debug('    file_path: %s', file_path)
+    logging.debug('    relative_path: %s', relative_path)
+    logging.debug('    Result: %s', result)
     return result
 
-def save_repo_to_text(path: str = '.', output_dir: Optional[str] = None, to_stdout: bool = False, cli_ignore_patterns: Optional[List[str]] = None) -> str:
+def save_repo_to_text(
+        path: str = '.',
+        output_dir: Optional[str] = None,
+        to_stdout: bool = False,
+        cli_ignore_patterns: Optional[List[str]] = None
+    ) -> str:
     """Save repository structure and contents to a text file.
     
     Args:
@@ -150,20 +197,24 @@ def save_repo_to_text(path: str = '.', output_dir: Optional[str] = None, to_stdo
     Returns:
         str: Path to the output file or the output text if to_stdout is True
     """
-    logging.debug(f'Starting to save repo structure to text for path: {path}')
-    gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(path, cli_ignore_patterns)
-    tree_structure = get_tree_structure(path, gitignore_spec, tree_and_content_ignore_spec)
-    tree_structure = remove_empty_dirs(tree_structure, path)
-    logging.debug(f'Final tree structure to be written: {tree_structure}')
-    
+    logging.debug('Starting to save repo structure to text for path: %s', path)
+    gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(
+        path, cli_ignore_patterns
+    )
+    tree_structure: str = get_tree_structure(
+        path, gitignore_spec, tree_and_content_ignore_spec
+    )
+    tree_structure = remove_empty_dirs(tree_structure)
+    logging.debug('Final tree structure to be written: %s', tree_structure)
+
     timestamp = datetime.now(timezone.utc).strftime('%Y-%m-%d-%H-%M-%S-UTC')
     output_file = f'repo-to-text_{timestamp}.txt'
-    
+
     if output_dir:
         if not os.path.exists(output_dir):
             os.makedirs(output_dir)
         output_file = os.path.join(output_dir, output_file)
-    
+
     output_content: List[str] = []
     project_name = os.path.basename(os.path.abspath(path))
     output_content.append(f'Directory: {project_name}\n\n')
@@ -172,7 +223,7 @@ def save_repo_to_text(path: str = '.', output_dir: Optional[str] = None, to_stdo
 
     if os.path.exists(os.path.join(path, '.gitignore')):
         output_content.append('├── .gitignore\n')
-    
+
     output_content.append(tree_structure + '\n' + '```\n')
     logging.debug('Tree structure written to output content')
 
@@ -180,47 +231,59 @@ def save_repo_to_text(path: str = '.', output_dir: Optional[str] = None, to_stdo
         for filename in files:
             file_path = os.path.join(root, filename)
             relative_path = os.path.relpath(file_path, path)
-            
-            if should_ignore_file(file_path, relative_path, gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec):
+
+            if should_ignore_file(
+                file_path,
+                relative_path,
+                gitignore_spec,
+                content_ignore_spec,
+                tree_and_content_ignore_spec
+            ):
                 continue
 
             relative_path = relative_path.replace('./', '', 1)
-            
+
             output_content.append(f'\nContents of {relative_path}:\n')
             output_content.append('```\n')
             try:
                 with open(file_path, 'r', encoding='utf-8') as f:
                     output_content.append(f.read())
             except UnicodeDecodeError:
-                logging.debug(f'Could not decode file contents: {file_path}')
+                logging.debug('Could not decode file contents: %s', file_path)
                 output_content.append('[Could not decode file contents]\n')
             output_content.append('\n```\n')
 
     output_content.append('\n')
     logging.debug('Repository contents written to output content')
-    
+
     output_text = ''.join(output_content)
-    
+
     if to_stdout:
         print(output_text)
         return output_text
 
-    with open(output_file, 'w') as file:
+    with open(output_file, 'w', encoding='utf-8') as file:
         file.write(output_text)
-    
+
     try:
-        import importlib.util
+        import importlib.util # pylint: disable=import-outside-toplevel
         if importlib.util.find_spec("pyperclip"):
-            import pyperclip # type: ignore
+            import pyperclip # pylint: disable=import-outside-toplevel # type: ignore
             pyperclip.copy(output_text) # type: ignore
             logging.debug('Repository structure and contents copied to clipboard')
         else:
             print("Tip: Install 'pyperclip' package to enable automatic clipboard copying:")
             print("     pip install pyperclip")
-    except Exception as e:
-        logging.warning('Could not copy to clipboard. You might be running this script over SSH or without clipboard support.')
-        logging.debug(f'Clipboard copy error: {e}')
-    
-    print(f"[SUCCESS] Repository structure and contents successfully saved to file: \"./{output_file}\"")
-    
-    return output_file 
\ No newline at end of file
+    except (ImportError) as e:
+        logging.warning(
+            'Could not copy to clipboard. You might be running this '
+            'script over SSH or without clipboard support.'
+        )
+        logging.debug('Clipboard copy error: %s', e)
+
+    print(
+        "[SUCCESS] Repository structure and contents successfully saved to "
+        f"file: \"./{output_file}\""
+    )
+
+    return output_file
diff --git a/repo_to_text/main.py b/repo_to_text/main.py
index f911293..b25086e 100644
--- a/repo_to_text/main.py
+++ b/repo_to_text/main.py
@@ -1,3 +1,5 @@
+"""This is the main entry point for the repo_to_text package."""
+
 from repo_to_text.cli.cli import main
 
 if __name__ == '__main__':
diff --git a/repo_to_text/utils/utils.py b/repo_to_text/utils/utils.py
index ea374a4..c37a058 100644
--- a/repo_to_text/utils/utils.py
+++ b/repo_to_text/utils/utils.py
@@ -1,3 +1,5 @@
+"""This module contains utility functions for the repo_to_text package."""
+
 import os
 import shutil
 import logging
@@ -19,7 +21,10 @@ def check_tree_command() -> bool:
         bool: True if tree command is available, False otherwise
     """
     if shutil.which('tree') is None:
-        print("The 'tree' command is not found. Please install it using one of the following commands:")
+        print(
+            "The 'tree' command is not found. "
+            + "Please install it using one of the following commands:"
+        )
         print("For Debian-based systems (e.g., Ubuntu): sudo apt-get install tree")
         print("For Red Hat-based systems (e.g., Fedora, CentOS): sudo yum install tree")
         return False
@@ -40,43 +45,38 @@ def is_ignored_path(file_path: str) -> bool:
     is_ignored_file = any(file_path.startswith(prefix) for prefix in ignored_files_prefix)
     result = is_ignored_dir or is_ignored_file
     if result:
-        logging.debug(f'Path ignored: {file_path}')
+        logging.debug('Path ignored: %s', file_path)
     return result
 
-def remove_empty_dirs(tree_output: str, path: str = '.') -> str:
-    """Remove empty directories from tree output.
-    
-    Args:
-        tree_output: Output from tree command
-        path: Base path for the tree
-        
-    Returns:
-        str: Tree output with empty directories removed
-    """
+def remove_empty_dirs(tree_output: str) -> str:
+    """Remove empty directories from tree output."""
     logging.debug('Removing empty directories from tree output')
     lines = tree_output.splitlines()
-    non_empty_dirs: Set[str] = set()
     filtered_lines: List[str] = []
 
+    # Track directories that have files or subdirectories
+    non_empty_dirs: Set[str] = set()
+
+    # First pass: identify non-empty directories
+    for line in reversed(lines):
+        stripped_line = line.strip()
+        if not stripped_line.endswith('/'):
+            # This is a file, mark its parent directory as non-empty
+            parent_dir: str = os.path.dirname(stripped_line)
+            while parent_dir:
+                non_empty_dirs.add(parent_dir)
+                parent_dir = os.path.dirname(parent_dir)
+
+    # Second pass: filter out empty directories
     for line in lines:
-        parts = line.strip().split()
-        if parts:
-            full_path = parts[-1]
-            if os.path.isdir(full_path) and not any(os.path.isfile(os.path.join(full_path, f)) for f in os.listdir(full_path)):
-                logging.debug(f'Directory is empty and will be removed: {full_path}')
+        stripped_line = line.strip()
+        if stripped_line.endswith('/'):
+            # This is a directory
+            dir_path = stripped_line[:-1]  # Remove trailing slash
+            if dir_path not in non_empty_dirs:
+                logging.debug('Directory is empty and will be removed: %s', dir_path)
                 continue
-            non_empty_dirs.add(os.path.dirname(full_path))
-            filtered_lines.append(line)
-    
-    final_lines: List[str] = []
-    for line in filtered_lines:
-        parts = line.strip().split()
-        if parts:
-            full_path = parts[-1]
-            if os.path.isdir(full_path) and full_path not in non_empty_dirs:
-                logging.debug(f'Directory is empty and will be removed: {full_path}')
-                continue
-            final_lines.append(line)
-    
+        filtered_lines.append(line)
+
     logging.debug('Empty directory removal complete')
-    return '\n'.join(filtered_lines) 
\ No newline at end of file
+    return '\n'.join(filtered_lines)
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 23747e5..b89db81 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -1,9 +1,11 @@
+"""Test the CLI module."""
+
 import os
-import pytest
 import tempfile
 import shutil
 from typing import Generator
 from unittest.mock import patch, MagicMock
+import pytest
 from repo_to_text.cli.cli import (
     create_default_settings_file,
     parse_args,
@@ -48,11 +50,11 @@ def test_create_default_settings_file(temp_dir: str) -> None:
     """Test creation of default settings file."""
     os.chdir(temp_dir)
     create_default_settings_file()
-    
+
     settings_file = '.repo-to-text-settings.yaml'
     assert os.path.exists(settings_file)
-    
-    with open(settings_file, 'r') as f:
+
+    with open(settings_file, 'r', encoding='utf-8') as f:
         content = f.read()
         assert 'gitignore-import-and-ignore: True' in content
         assert 'ignore-tree-and-content:' in content
@@ -63,7 +65,7 @@ def test_create_default_settings_file_already_exists(temp_dir: str) -> None:
     os.chdir(temp_dir)
     # Create the file first
     create_default_settings_file()
-    
+
     # Try to create it again
     with pytest.raises(FileExistsError) as exc_info:
         create_default_settings_file()
@@ -94,7 +96,10 @@ def test_main_create_settings(mock_create_settings: MagicMock) -> None:
 
 @patch('repo_to_text.cli.cli.setup_logging')
 @patch('repo_to_text.cli.cli.create_default_settings_file')
-def test_main_with_debug_logging(mock_create_settings: MagicMock, mock_setup_logging: MagicMock) -> None:
+def test_main_with_debug_logging(
+    mock_create_settings: MagicMock,
+    mock_setup_logging: MagicMock
+) -> None:
     """Test main function with debug logging enabled."""
     with patch('sys.argv', ['repo-to-text', '--debug', '--create-settings']):
         with pytest.raises(SystemExit) as exc_info:
@@ -104,4 +109,4 @@ def test_main_with_debug_logging(mock_create_settings: MagicMock, mock_setup_log
         mock_create_settings.assert_called_once()
 
 if __name__ == "__main__":
-    pytest.main([__file__]) 
\ No newline at end of file
+    pytest.main([__file__])
diff --git a/tests/test_core.py b/tests/test_core.py
index aa05e3d..5c38bdd 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1,8 +1,11 @@
+"""Test the core module."""
+
 import os
 import tempfile
 import shutil
-import pytest
 from typing import Generator
+import pytest
+
 from repo_to_text.core.core import (
     get_tree_structure,
     load_ignore_specs,
@@ -20,12 +23,13 @@ def temp_dir() -> Generator[str, None, None]:
     shutil.rmtree(temp_path)
 
 @pytest.fixture
-def sample_repo(temp_dir: str) -> str:
+def sample_repo(tmp_path: str) -> str:
     """Create a sample repository structure for testing."""
+    tmp_path_str = str(tmp_path)
     # Create directories
-    os.makedirs(os.path.join(temp_dir, "src"))
-    os.makedirs(os.path.join(temp_dir, "tests"))
-    
+    os.makedirs(os.path.join(tmp_path_str, "src"))
+    os.makedirs(os.path.join(tmp_path_str, "tests"))
+
     # Create sample files
     files = {
         "README.md": "# Test Project",
@@ -45,14 +49,14 @@ ignore-content:
   - "README.md"
 """
     }
-    
+
     for file_path, content in files.items():
-        full_path = os.path.join(temp_dir, file_path)
+        full_path = os.path.join(tmp_path_str, file_path)
         os.makedirs(os.path.dirname(full_path), exist_ok=True)
-        with open(full_path, "w") as f:
+        with open(full_path, "w", encoding='utf-8') as f:
             f.write(content)
-    
-    return temp_dir
+
+    return tmp_path_str
 
 def test_is_ignored_path() -> None:
     """Test the is_ignored_path function."""
@@ -64,26 +68,26 @@ def test_is_ignored_path() -> None:
 def test_load_ignore_specs(sample_repo: str) -> None:
     """Test loading ignore specifications from files."""
     gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(sample_repo)
-    
+
     assert gitignore_spec is not None
     assert content_ignore_spec is not None
     assert tree_and_content_ignore_spec is not None
-    
+
     # Test gitignore patterns
     assert gitignore_spec.match_file("test.pyc") is True
     assert gitignore_spec.match_file("__pycache__/cache.py") is True
     assert gitignore_spec.match_file(".git/config") is True
-    
+
     # Test content ignore patterns
     assert content_ignore_spec.match_file("README.md") is True
-    
+
     # Test tree and content ignore patterns
     assert tree_and_content_ignore_spec.match_file(".git/config") is True
 
 def test_should_ignore_file(sample_repo: str) -> None:
     """Test file ignoring logic."""
     gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(sample_repo)
-    
+
     # Test various file paths
     assert should_ignore_file(
         ".git/config",
@@ -92,7 +96,7 @@ def test_should_ignore_file(sample_repo: str) -> None:
         content_ignore_spec,
         tree_and_content_ignore_spec
     ) is True
-    
+
     assert should_ignore_file(
         "src/main.py",
         "src/main.py",
@@ -105,7 +109,7 @@ def test_get_tree_structure(sample_repo: str) -> None:
     """Test tree structure generation."""
     gitignore_spec, _, tree_and_content_ignore_spec = load_ignore_specs(sample_repo)
     tree_output = get_tree_structure(sample_repo, gitignore_spec, tree_and_content_ignore_spec)
-    
+
     # Basic structure checks
     assert "src" in tree_output
     assert "tests" in tree_output
@@ -113,74 +117,74 @@ def test_get_tree_structure(sample_repo: str) -> None:
     assert "test_main.py" in tree_output
     assert ".git" not in tree_output
 
-def test_remove_empty_dirs(temp_dir: str) -> None:
+def test_remove_empty_dirs(tmp_path: str) -> None:
     """Test removal of empty directories from tree output."""
     # Create test directory structure
-    os.makedirs(os.path.join(temp_dir, "src"))
-    os.makedirs(os.path.join(temp_dir, "empty_dir"))
-    os.makedirs(os.path.join(temp_dir, "tests"))
-    
+    os.makedirs(os.path.join(tmp_path, "src"))
+    os.makedirs(os.path.join(tmp_path, "empty_dir"))
+    os.makedirs(os.path.join(tmp_path, "tests"))
+
     # Create some files
-    with open(os.path.join(temp_dir, "src/main.py"), "w") as f:
+    with open(os.path.join(tmp_path, "src/main.py"), "w", encoding='utf-8') as f:
         f.write("print('test')")
-    with open(os.path.join(temp_dir, "tests/test_main.py"), "w") as f:
+    with open(os.path.join(tmp_path, "tests/test_main.py"), "w", encoding='utf-8') as f:
         f.write("def test(): pass")
-    
+
     # Create a mock tree output that matches the actual tree command format
     tree_output = (
-        f"{temp_dir}\n"
-        f"├── {os.path.join(temp_dir, 'src')}\n"
-        f"│   └── {os.path.join(temp_dir, 'src/main.py')}\n"
-        f"├── {os.path.join(temp_dir, 'empty_dir')}\n"
-        f"└── {os.path.join(temp_dir, 'tests')}\n"
-        f"    └── {os.path.join(temp_dir, 'tests/test_main.py')}\n"
+        f"{tmp_path}\n"
+        f"├── {os.path.join(tmp_path, 'src')}\n"
+        f"│   └── {os.path.join(tmp_path, 'src/main.py')}\n"
+        f"├── {os.path.join(tmp_path, 'empty_dir')}\n"
+        f"└── {os.path.join(tmp_path, 'tests')}\n"
+        f"    └── {os.path.join(tmp_path, 'tests/test_main.py')}\n"
     )
-    
-    filtered_output = remove_empty_dirs(tree_output, temp_dir)
-    
+
+    filtered_output = remove_empty_dirs(tree_output)
+
     # Check that empty_dir is removed but other directories remain
     assert "empty_dir" not in filtered_output
-    assert os.path.join(temp_dir, "src") in filtered_output
-    assert os.path.join(temp_dir, "tests") in filtered_output
-    assert os.path.join(temp_dir, "src/main.py") in filtered_output
-    assert os.path.join(temp_dir, "tests/test_main.py") in filtered_output
+    assert os.path.join(tmp_path, "src") in filtered_output
+    assert os.path.join(tmp_path, "tests") in filtered_output
+    assert os.path.join(tmp_path, "src/main.py") in filtered_output
+    assert os.path.join(tmp_path, "tests/test_main.py") in filtered_output
 
 def test_save_repo_to_text(sample_repo: str) -> None:
     """Test the main save_repo_to_text function."""
     # Create output directory
     output_dir = os.path.join(sample_repo, "output")
     os.makedirs(output_dir, exist_ok=True)
-    
+
     # Create .git directory to ensure it's properly ignored
     os.makedirs(os.path.join(sample_repo, ".git"))
-    with open(os.path.join(sample_repo, ".git/config"), "w") as f:
+    with open(os.path.join(sample_repo, ".git/config"), "w", encoding='utf-8') as f:
         f.write("[core]\n\trepositoryformatversion = 0\n")
-    
+
     # Test file output
     output_file = save_repo_to_text(sample_repo, output_dir=output_dir)
     assert os.path.exists(output_file)
     assert os.path.dirname(output_file) == output_dir
-    
+
     # Check file contents
-    with open(output_file, 'r') as f:
+    with open(output_file, 'r', encoding='utf-8') as f:
         content = f.read()
-        
+
         # Basic content checks
         assert "Directory Structure:" in content
-        
+
         # Check for expected files
         assert "src/main.py" in content
         assert "tests/test_main.py" in content
-        
+
         # Check for file contents
         assert "print('Hello World')" in content
         assert "def test_sample(): pass" in content
-        
+
         # Ensure ignored patterns are not in output
         assert ".git/config" not in content  # Check specific file
         assert "repo-to-text_" not in content
         assert ".repo-to-text-settings.yaml" not in content
-        
+
         # Check that .gitignore content is not included
         assert "*.pyc" not in content
         assert "__pycache__" not in content
@@ -197,14 +201,16 @@ def test_load_ignore_specs_with_cli_patterns(sample_repo: str) -> None:
     """Test loading ignore specs with CLI patterns."""
     cli_patterns = ["*.log", "temp/"]
     _, _, tree_and_content_ignore_spec = load_ignore_specs(sample_repo, cli_patterns)
-    
+
     assert tree_and_content_ignore_spec.match_file("test.log") is True
     assert tree_and_content_ignore_spec.match_file("temp/file.txt") is True
     assert tree_and_content_ignore_spec.match_file("normal.txt") is False
 
 def test_load_ignore_specs_without_gitignore(temp_dir: str) -> None:
     """Test loading ignore specs when .gitignore is missing."""
-    gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(temp_dir)
+    gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(
+        temp_dir
+    )
     assert gitignore_spec is None
     assert content_ignore_spec is None
     assert tree_and_content_ignore_spec is not None
@@ -214,9 +220,9 @@ def test_get_tree_structure_with_special_chars(temp_dir: str) -> None:
     # Create files with special characters
     special_dir = os.path.join(temp_dir, "special chars")
     os.makedirs(special_dir)
-    with open(os.path.join(special_dir, "file with spaces.txt"), "w") as f:
+    with open(os.path.join(special_dir, "file with spaces.txt"), "w", encoding='utf-8') as f:
         f.write("test")
-    
+
     tree_output = get_tree_structure(temp_dir)
     assert "special chars" in tree_output
     assert "file with spaces.txt" in tree_output
@@ -224,7 +230,7 @@ def test_get_tree_structure_with_special_chars(temp_dir: str) -> None:
 def test_should_ignore_file_edge_cases(sample_repo: str) -> None:
     """Test edge cases for should_ignore_file function."""
     gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(sample_repo)
-    
+
     # Test with dot-prefixed paths
     assert should_ignore_file(
         "./src/main.py",
@@ -233,7 +239,7 @@ def test_should_ignore_file_edge_cases(sample_repo: str) -> None:
         content_ignore_spec,
         tree_and_content_ignore_spec
     ) is False
-    
+
     # Test with absolute paths
     abs_path = os.path.join(sample_repo, "src/main.py")
     rel_path = "src/main.py"
@@ -252,9 +258,9 @@ def test_save_repo_to_text_with_binary_files(temp_dir: str) -> None:
     binary_content = b'\x00\x01\x02\x03'
     with open(binary_path, "wb") as f:
         f.write(binary_content)
-    
+
     output = save_repo_to_text(temp_dir, to_stdout=True)
-    
+
     # Check that the binary file is listed in the structure
     assert "binary.bin" in output
     # Check that the file content section exists with raw binary content
@@ -264,13 +270,13 @@ def test_save_repo_to_text_with_binary_files(temp_dir: str) -> None:
 def test_save_repo_to_text_custom_output_dir(temp_dir: str) -> None:
     """Test save_repo_to_text with custom output directory."""
     # Create a simple file structure
-    with open(os.path.join(temp_dir, "test.txt"), "w") as f:
+    with open(os.path.join(temp_dir, "test.txt"), "w", encoding='utf-8') as f:
         f.write("test content")
-    
+
     # Create custom output directory
     output_dir = os.path.join(temp_dir, "custom_output")
     output_file = save_repo_to_text(temp_dir, output_dir=output_dir)
-    
+
     assert os.path.exists(output_file)
     assert os.path.dirname(output_file) == output_dir
     assert output_file.startswith(output_dir)
diff --git a/tests/test_utils.py b/tests/test_utils.py
index c6a5ff8..43a772d 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,6 +1,10 @@
+"""Test the utils module."""
+
 import logging
-import pytest
 from typing import Generator
+import io
+import pytest
+
 from repo_to_text.utils.utils import setup_logging
 
 @pytest.fixture(autouse=True)
@@ -20,7 +24,7 @@ def test_setup_logging_debug() -> None:
     root_logger = logging.getLogger()
     root_logger.handlers.clear()  # Clear existing handlers
     root_logger.setLevel(logging.WARNING)  # Reset to default
-    
+
     setup_logging(debug=True)
     assert len(root_logger.handlers) > 0
     assert root_logger.level == logging.DEBUG
@@ -30,7 +34,7 @@ def test_setup_logging_info() -> None:
     root_logger = logging.getLogger()
     root_logger.handlers.clear()  # Clear existing handlers
     root_logger.setLevel(logging.WARNING)  # Reset to default
-    
+
     setup_logging(debug=False)
     assert len(root_logger.handlers) > 0
     assert root_logger.level == logging.INFO
@@ -40,14 +44,14 @@ def test_setup_logging_formatter() -> None:
     setup_logging(debug=True)
     logger = logging.getLogger()
     handlers = logger.handlers
-    
+
     # Check if there's at least one handler
     assert len(handlers) > 0
-    
+
     # Check formatter
     formatter = handlers[0].formatter
     assert formatter is not None
-    
+
     # Test format string
     test_record = logging.LogRecord(
         name='test',
@@ -66,26 +70,27 @@ def test_setup_logging_multiple_calls() -> None:
     """Test that multiple calls to setup_logging don't create duplicate handlers."""
     root_logger = logging.getLogger()
     root_logger.handlers.clear()
-    
+
     setup_logging(debug=True)
     initial_handler_count = len(root_logger.handlers)
-    
+
     # Call setup_logging again
     setup_logging(debug=True)
-    assert len(root_logger.handlers) == initial_handler_count, "Should not create duplicate handlers"
+    assert len(root_logger.handlers) == \
+        initial_handler_count, "Should not create duplicate handlers"
 
 def test_setup_logging_level_change() -> None:
     """Test changing log levels between setup_logging calls."""
     root_logger = logging.getLogger()
     root_logger.handlers.clear()
-    
+
     # Start with debug
     setup_logging(debug=True)
     assert root_logger.level == logging.DEBUG
-    
+
     # Clear handlers before next setup
     root_logger.handlers.clear()
-    
+
     # Switch to info
     setup_logging(debug=False)
     assert root_logger.level == logging.INFO
@@ -94,24 +99,25 @@ def test_setup_logging_message_format() -> None:
     """Test the actual format of logged messages."""
     setup_logging(debug=True)
     logger = logging.getLogger()
-    
+
     # Create a temporary handler to capture output
-    import io
     log_capture = io.StringIO()
     handler = logging.StreamHandler(log_capture)
     # Use formatter that includes pathname
-    handler.setFormatter(logging.Formatter('%(levelname)s %(name)s:%(pathname)s:%(lineno)d %(message)s'))
+    handler.setFormatter(
+        logging.Formatter('%(levelname)s %(name)s:%(pathname)s:%(lineno)d %(message)s')
+    )
     logger.addHandler(handler)
-    
+
     # Ensure debug level is set
     logger.setLevel(logging.DEBUG)
     handler.setLevel(logging.DEBUG)
-    
+
     # Log a test message
     test_message = "Test log message"
     logger.debug(test_message)
     log_output = log_capture.getvalue()
-    
+
     # Verify format components
     assert test_message in log_output
     assert "DEBUG" in log_output
@@ -121,22 +127,21 @@ def test_setup_logging_error_messages() -> None:
     """Test logging of error messages."""
     setup_logging(debug=False)
     logger = logging.getLogger()
-    
+
     # Create a temporary handler to capture output
-    import io
     log_capture = io.StringIO()
     handler = logging.StreamHandler(log_capture)
     handler.setFormatter(logger.handlers[0].formatter)
     logger.addHandler(handler)
-    
+
     # Log an error message
     error_message = "Test error message"
     logger.error(error_message)
     log_output = log_capture.getvalue()
-    
+
     # Error messages should always be logged regardless of debug setting
     assert error_message in log_output
     assert "ERROR" in log_output
 
 if __name__ == "__main__":
-    pytest.main([__file__]) 
\ No newline at end of file
+    pytest.main([__file__])