Andres Leon Rangel aleon1220

Python testing reference

This document is a reference for common testing patterns in a Django/Python project using Pytest.

Contents:

Set-up and tear-down

Permanent WSL DNS Fix (WSL 2.2.1+)

If you're encountering ping github.com failing inside WSL with a Temporary failure in name resolution, you're not alone — this has been a long-standing issue, especially when using VPNs or corporate networks.

This issue is now fixed robustly with DNS tunneling, which preserves dynamic DNS behavior and avoids limitations like WSL’s former hard cap of 3 DNS servers in /etc/resolv.conf.

DNS tunneling is enabled by default in WSL version 2.2.1 and later, meaning that if you're still seeing DNS resolution issues, the first and most effective fix is simply to upgrade WSL. Upgrading WSL updates the WSL platform itself, but does not affect your installed Linux distributions, apps, or files.

To upgrade WSL, follow these steps,

Problem

You have installed GPG, then tried to commit and suddenly you see this error message after it:

error: gpg failed to sign the data
fatal: failed to write commit object

Debug

How to setup SFTP Logging on Ubuntu 14.04 for a Chrooted User

Prerequisites: Using internal-sftp for sftp; rsyslog for logging

Step 1. Set up your chrooted directories

sudo mkdir /sftp/myshare
sudo mkdir /sftp/myothershare

Step 2. Create your groups for your chrooted users

Typing vagrant from the command line will display a list of all available commands.

Be sure that you are in the same directory as the Vagrantfile when running these commands!

Creating a VM

vagrant init -- Initialize Vagrant with a Vagrantfile and ./.vagrant directory, using no specified base image. Before you can do vagrant up, you'll need to specify a base image in the Vagrantfile.
vagrant init <boxpath> -- Initialize Vagrant with a specific box. To find a box, go to the public Vagrant box catalog. When you find one you like, just replace it's name with boxpath. For example, vagrant init ubuntu/trusty64.

Starting a VM

vagrant up -- starts vagrant environment (also provisions only on the FIRST vagrant up)

	# Python start-up file
	# --------------------
	# Ensure a PYTHONSTARTUP environment variable points to the location of this file.
	# See https://docs.python.org/3/using/cmdline.html#envvar-PYTHONSTARTUP

	# Always have pp available
	from pprint import pprint as pp

	# Pre-emptively import datetime as I use it a lot.
	import datetime

	#!/bin/bash
	set -o errexit

	source ./library
	# Entry point of the script.
	# If makes sure that the user supplied the right
	# amount of arguments (image_name)
	# and then performs the main workflow:
	# 1. retrieve the image digest
	# 2. retrieve the layer info of image