add phpunit tests and composer
Merge pull request #3 from johnikx/tests_and_composer

add phpunit tests and composer
add tests for edge cases
Merge pull request #5 from johnikx/missing_tests

add tests for edge cases
composer.lock should not be ignored : https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file
Cleanup