Add CRON validation function testing. #2

	name: Build Docker Image

	on:
	# run it during pull request
	pull_request:

	workflow_dispatch:

	jobs:
	# define job to build and publish docker image
	build-docker-image:
	name: Build Docker image only
	# run only when code is compiling and tests are passing
	runs-on: ubuntu-latest

	# steps to perform in job
	steps:
	- name: Checkout code
	uses: actions/checkout@v4

	- name: Test CRON validation.
	run: bash docker/src/tests/test-cron-validation.sh

	- name: Force permissions fix.
	run: sudo apt-get update && sudo apt-get install dos2unix -y && cd docker && bash dos2unix.sh

	# setup Docker build action
	- name: Set up Docker Buildx
	id: buildx
	uses: docker/setup-buildx-action@v3

	- name: Build image only
	uses: docker/build-push-action@v5
	with:
	context: ./docker
	push: false

	- name: Image digest
	run: echo ${{ steps.docker_build.outputs.digest }}

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