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 Create a Mock Virtualenv with an Activation Script in Python
Create a mock virtualenv directory with a generated bash activation script using Python's standard library.
import os
import subprocess
import sys
from pathlib import Path
def mock_virtualenv(name: str = "myenv") -> Path:
"""Create a mock virtualenv directory and activation script."""
env_dir = Path(name)
env_dir.mkdir(exist_ok=True)
(env_dir / "bin").mkdir(exist_ok=True)
activate_script = f"""#!/bin/…How to Mock Click CLI App Subcommands in Python
Simulate Click-style CLI subcommand calls in Python by using argparse with subparsers and mocking sys.argv in tests or scripts.
import sys
import argparse
def do_greet(args):
print(f"Hello, {args.name}!")
def do_goodbye(args):
print(f"Goodbye, {args.name}!")
def main():
parser = argparse.ArgumentParser(prog="clickapp")
subparsers = parser.add_subparsers(dest="command", required=True)
greet_parser = subparsers.add_par…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 configure ruff linter rules in pyproject.toml with Python
This Python script generates a pyproject.toml file with ruff linter rules, including selected and ignored rules, per-file ignores, and complexity limits.
from pathlib import Path
def configure_ruff_rules(project_dir: str = "my_project") -> None:
"""Create a pyproject.toml with ruff linter rules for mock usage."""
pyproject_path = Path(project_dir) / "pyproject.toml"
pyproject_path.parent.mkdir(parents=True, exist_ok=True)
config = """[tool.ruff]
line-…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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This page collects modern tooling snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
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