mv test file to src

improve doc

.gitlab-ci.yml

+# This is a demo for integrating pylint results into GitLab. For more information see:
+# related Bits and Bytes article: [TODO: **BnB link**]
+# GitLab documentation          : https://docs.gitlab.com/ee/ci/testing/code_quality.html
+#
+# pylint        (python linter)                          : https://pylint.org
+# pylint-exit   (for analysing pylint exit code)         : https://github.com/jongracecox/pylint-exit
+# pylint-gitlab (for exporting pylint results for GitLab): https://gitlab.com/smueller18/pylint-gitlab
+
+
 pylint:
   image: python:3
   variables:
     PIP_CACHE_DIR: ${CI_PROJECT_DIR}/.pipcache
   before_script:
+    # ideally you should install these tools in your CI container once and reuse it
     - pip install pylint pylint-exit pylint-gitlab
   script:
-    - pylint *.py || pylint-exit $?
+    - pylint src/*.py || pylint-exit $?
   after_script:
-    - pylint --exit-zero --load-plugins=pylint_gitlab --output-format=gitlab-codeclimate:codeclimate.json *.py
+    - pylint --load-plugins=pylint_gitlab --output-format=gitlab-codeclimate:codeclimate.json src/*.py
   artifacts:
     reports:
       codequality: codeclimate.json
     when: always
   tags:
+    # run this job only on the runners with distributed cache
     - distributedcache
   cache:
     when: always