Test a GitLab-CI deploy with env vars

.gitlab-ci.yml

stages:
    - deploy

deploy:
    stage: deploy
    only: [master]

    before_script:
        # SSH setup
        - mkdir -p ~/.ssh
        - echo "$DEPLOY_PRIVATEKEY" > ~/.ssh/id_rsa
        - echo -e "$DEPLOY_HOSTKEY" | tr -d '\r' > ~/.ssh/known_hosts
        - echo -e "Host *\n\tStrictHostKeyChecking no\n\tPort $DEPLOY_PORT\n\n" > ~/.ssh/config
        - chmod 700 -R ~/.ssh/

      script:
        # Now deploy your stuff

Makefile

define DEPLOY_PRIVATEKEY
-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
QyNTUxOQAAACAtAB/tFaS2zHcMYKJpd3evq3fD6ZQOdHwt9tndhyPj/AAAAJBVYylwVWMp
cAAAAAtzc2gtZWQyNTUxOQAAACAtAB/tFaS2zHcMYKJpd3evq3fD6ZQOdHwt9tndhyPj/A
AAAEAkp03Vby1VmGDl3Y3/0eh6P7xAte2bHEvMQ2aWWnnzAi0AH+0VpLbMdwxgoml3d6+r
d8PplA50fC322d2HI+P8AAAAB2V4YW1wbGUBAgMEBQY=
-----END OPENSSH PRIVATE KEY-----
endef
export DEPLOY_PRIVATEKEY

define DEPLOY_HOSTKEY
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIC0AH+0VpLbMdwxgoml3d6+rd8PplA50fC322d2HI+P8 example
endef
export DEPLOY_HOSTKEY

define DEPLOY_USERNAME
ssh-user
endef
export DEPLOY_USERNAME

define DEPLOY_HOST
example.host
endef
export DEPLOY_HOST

define DEPLOY_PORT
22
endef
export DEPLOY_PORT

.PHONY: test_deploy
test_deploy:
	gitlab-runner exec docker \
		--env "DEPLOY_PRIVATEKEY=$$DEPLOY_PRIVATEKEY" \
		--env "DEPLOY_HOSTKEY=$$DEPLOY_HOSTKEY" \
		--env "DEPLOY_USERNAME=$$DEPLOY_USERNAME" \
		--env "DEPLOY_HOST=$$DEPLOY_HOST" \
		--env "DEPLOY_PORT=$$DEPLOY_PORT" \
		deploy