Add regression test (diff), Github workflow and scripts #1

	name: Regression Diff Test
	on: [push]

	jobs:
	regression_diff_test:
	runs-on: ubuntu-22.04
	steps:
	- uses: actions/checkout@v4
	with:
	fetch-depth: 0

	- name: Setup Python
	uses: actions/setup-python@v4
	with:
	python-version: 3.10.x

	- name: Install dependencies
	run: \|
	python -V
	pip install -r requirements.txt

	- name: Install ifex module and prepare
	run: \|
	python setup.py develop
	mkdir difftest
	# We have to copy the script because
	# 1. It might not even exist in the compared version
	# 2. If it exists, we want to run the same version on both
	cp .github/workflows/regression_diff_test.sh ./script_to_run.sh

	- name: Run generation steps on new code
	run: \|
	./script_to_run.sh >difftest/new

	- name: Run generation steps on compared (old) code
	run: \|
	git fetch ${{ github.event.before }}
	git checkout -q ${{ github.event.before }} && git rev-parse HEAD >difftest/previous && ./script_to_run.sh >>difftest/previous \|\| true
	git fetch origin/master
	git checkout -q origin/master && git rev-parse HEAD >difftest/origin_master && ./script_to_run.sh >difftest/origin_master \|\| true

	- name: Diff against HEAD~1
	run: \|
	cd difftest
	diff previous new \|\| true

	- name: Diff against origin/master
	run: \|
	cd difftest
	diff origin_master new \|\| true

	- name: Upload files
	uses: actions/upload-artifact@v3
	with:
	name: difftest
	path: difftest

Provide feedback