Modern tooling
uv, ruff, pyproject.toml, packaging, and current Python project workflows.
Build a Recipe Runner Mock in Python
A Python script that mocks a command runner recipe system: maps recipe names to shell commands, executes them with subprocess, and prints the output and exit code.
import subprocess
import sys
def run_recipe(recipe: str) -> None:
"""Simulate a command runner recipe by printing the command and exit code."""
print(f"Running recipe: {recipe}")
result = subprocess.run(recipe, shell=True, capture_output=True, text=True)
print(f"Exit code: {result.returncode}")
i…How to Build a Wheel with Hatchling in Python
Build a Python wheel using the hatchling build backend and the build package, handling missing project metadata automatically.
import subprocess
import sys
import tempfile
from pathlib import Path
def build_wheel_with_hatchling(project_dir: str) -> str:
"""Build a wheel using hatchling and return the wheel file path."""
project_path = Path(project_dir)
# Simulate a minimal project structure if missing
if not (project_path /…How to Define Nox Sessions in Python
Automate repetitive tasks like testing and linting with reusable Nox sessions.
import nox
@nox.session(python=["3.9", "3.10"])
def tests(session):
session.install("pytest")
session.run("pytest")
@nox.session(python="3.9")
def lint(session):
session.install("ruff")
session.run("ruff", "check", ".")
if __name__ == "__main__":
print("Nox sessions defined: tests, lint")
…How to Load and Save CSV and JSON Files in Python
A beginner-friendly data helper that loads or saves CSV and JSON files using only the Python standard library, with automatic format detection from the file extension.
from pathlib import Path
import json
import csv
def load_data(file_path):
"""Load CSV or JSON data from disk based on file extension."""
path = Path(file_path)
if path.suffix == ".json":
with path.open() as f:
return json.load(f)
elif path.suffix == ".csv":
with path.open(…How to Mock Fabric Connections in Python for Task Testing
Create a lightweight MockConnection class to replace fabric.Connection and test task functions without SSH.
from fabric import Connection
class MockConnection:
"""Minimal mock of fabric.Connection for task testing."""
def __init__(self):
self.commands = []
def run(self, command, **kwargs):
self.commands.append(command)
return f"OK: {command}"
def deploy(conn):
"""Deploy the app:…How to Mock a PEP 517 Build Backend in Python
Use unittest.mock.Mock to simulate a PEP 517 backend interface, stub build hooks, and verify calls for package build automation.
import json
from unittest.mock import Mock
# Simulate a PEP 517 backend interface
class Pep517Backend:
def build_wheel(self, wheel_directory, config_settings=None, metadata_directory=None):
return f"{wheel_directory}/mock_package-1.0.0-py3-none-any.whl"
def get_requires_for_build_wheel(self, config_s…How to Mock a semantic-release Changelog in Python
This Python code simulates a semantic-release changelog generator, grouping commits by type and formatting them into a markdown changelog.
import json
from datetime import datetime
class SemanticReleaseChangelog:
def __init__(self, version, commits):
self.version = version
self.commits = commits
self.release_date = datetime.now().isoformat()
def generate_changelog(self):
grouped = {}
for commit in self.c…How to Use prompt_toolkit Autocomplete in Python
Demonstrates an interactive command-line prompt with autocomplete using prompt_toolkit's WordCompleter and a mock dataset.
from prompt_toolkit import prompt
from prompt_toolkit.completion import WordCompleter
def main():
"""Demo of prompt_toolkit autocomplete with a mock dataset."""
# A simple mock "database" of programming languages
languages = [
"Python", "Java", "JavaScript", "TypeScript", "C++", "C#",
"Go"…Lint a Dockerfile with a Mock Hadolint in Python
A lightweight Python script that simulates hadolint by scanning Dockerfile text for common lint rules and printing violations.
import subprocess
import tempfile
from pathlib import Path
def lint_dockerfile(content: str) -> list[str]:
"""Mock hadolint by checking a few rules and returning violations."""
violations = []
lines = content.splitlines()
for idx, line in enumerate(lines, start=1):
stripped = line.strip()
…Makefile Targets for lint, test, and build in Python
This Python script defines common Makefile targets (lint, test, build) as subprocess commands, printing each target's command and executing them with error checking.
import subprocess
TARGETS = {
"lint": ["ruff", "check", "."],
"test": ["pytest", "-q"],
"build": ["python", "-m", "build"],
}
def run(target: str) -> None:
if target not in TARGETS:
raise ValueError(f"Unknown target: {target}")
print(f"Running {target}...")
subprocess.run(TARGETS[tar…Browse by section
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Modern tooling — Python code examples
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