.gitlab-ci.yml: added docker:test

.gitlab-ci.yml

@@ -197,25 +197,49 @@ build:macOS:
     - pip3 install -U requests
     - python3 ./ci/gh_actions.py ${CI_COMMIT_REF_NAME} ${CI_COMMIT_SHA}
 
-docker:
+
+.docker: &docker
   <<: *nodep
-  stage: build
-  image: docker:latest
   <<: *multi_platform
+  image: docker:latest
+  variables:
+    DOCKER_IMAGE_NAME: knot-resolver-test:${PLATFORM}
   only:
     refs:
       - branches@knot/knot-resolver
   tags:
     - ${PLATFORM}
     - dind
-  variables:
-    DOCKER_IMAGE_NAME: knot-resolver-test:${CI_COMMIT_SHA}
+
+docker:build:
+  <<: *docker
+  stage: build
   script:
     - docker build --no-cache -t ${DOCKER_IMAGE_NAME} .
-    # TODO: perhaps try if the running image answers queries
+    - docker save ${DOCKER_IMAGE_NAME} -o ${DOCKER_IMAGE_NAME}.tar
+  artifacts:
+    paths:
+      - ${DOCKER_IMAGE_NAME}.tar
+
   after_script:  # remove dangling images to avoid running out of disk space
     - docker rmi ${DOCKER_IMAGE_NAME}
     - docker rmi $(docker images -f "dangling=true" -q)
+
+docker:test:
+  <<: *docker
+  stage: test
+  needs:
+    - docker:build
+  before_script:
+    - apk add --update bind-tools
+  script:
+    - docker load -i ${DOCKER_IMAGE_NAME}.tar
+    - docker run --rm -d -p 2375:53 ${DOCKER_IMAGE_NAME}
+    - docker ps
+    - dig example.com A @localhost#2375
+  after_script:
+    - docker stop $(docker ps -a -q)
+
 # }}}
 
 # sanity {{{