add tests

.gitlab-ci.yml

Dockerfile.test

README.md

coverage/coverage.json

coverage/lcov-report/base.css

coverage/lcov-report/index.html

coverage/lcov-report/lib/config.js.html

coverage/lcov-report/lib/form.js.html

coverage/lcov-report/lib/index.html

coverage/lcov-report/lib/lib.js.html

coverage/lcov-report/lib/math.js.html

coverage/lcov-report/prettify.css

coverage/lcov-report/prettify.js

coverage/lcov-report/sort-arrow-sprite.png

coverage/lcov-report/sorter.js

coverage/lcov.info

lib/config.js

lib/form.js

lib/lib.js

lib/math.js