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Testing & modern typing

pytest basics, mocks, type hints, TypedDict, Protocol, and static-checking patterns.

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How to Mock pathlib Path.read_text with mock_open in Python

Mock pathlib.Path.read_text using patch and mock_open to test file-reading code without touching the filesystem.

testing mock pathlib
Python 
import pathlib
from unittest.mock import mock_open, patch

def read_config(filepath: pathlib.Path) -> str:
    """Read file content with pathlib."""
    return filepath.read_text()

if __name__ == "__main__":
    mock_data = "version: 1.0\nname: demo-app"
    
    with patch("pathlib.Path.open", mock_open(read_data=mo…
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