added relation #602

	name: Validate PR
	on: pull_request

	defaults:
	run:
	shell: bash
	working-directory: project

	jobs:
	test:
	runs-on: ubuntu-latest
	steps:
	# checkout code
	- name: Checkout
	uses: actions/checkout@v3
	with:
	path: project
	fetch-depth: 2
	# checkout schema as xmllint can't https
	- name: Checkout schema repo
	uses: actions/checkout@v3
	with:
	repository: BetaMasaheft/Schema
	path: schema
	- name: Install Test Dependencies
	run: \|
	sudo apt-get update
	sudo apt-get install -y libxml2-utils
	# Compare locally changed files to PR's base
	- name: Check for changed source files
	id: changed
	run: \|
	echo "::set-output name=files::$( \
	git diff --name-only --diff-filter=ACMRT \
	${{ github.event.pull_request.base.sha }} \
	${{ github.sha }} -- ':./*/.xml' ':!./*/transkribus.xml' ':!./*/facsimile.xml' ':!.//edition.xml' ':!.//msDesc.xml' ':!./*/text.xml' \| xargs)"
	# Validate changed files against latest schema
	- name: Validate changed source files
	if: ${{ steps.changed.outputs.files != '' }}
	run: \|
	xmllint \
	--noout --xinclude --nowarning \
	--relaxng ../schema/tei-betamesaheft.rng \
	${{ steps.changed.outputs.files }} \
	2>&1 \| \
	{ grep -vE 'RNG\|validates' \|\| :; }
	# If no xml files were modified
	- name: No source files changed
	if: ${{ steps.changed.outputs.files == '' }}
	run: \|
	echo "All good"
	# ensure branch conaints only well-formed xml files
	- name: Ensure all XML files are well formed
	run: \|
	xmllint --noout \
	$(find . -type f -name '*.xml')

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