complete tests

[peter279k]

Changed log

• change the higher PHPUnit version because it fixes the count function problem for PHP version 7.2.
  This is the Travis build log before updating the PHPUnit version.
  And here is the new Travis build log after using the PHPUnit version 6.5+.
• integrate the code coverage service coveralls for this package.
  Here is the code coverage report generated by coveralls.
• add more tests.

[pascaldevink]

Could you remove this file please? Or even better, add it to the .gitignore file?
Although this is nice of course, it is very specific for a (set of) editors, whilst ignoring others. Next to that, I'd much rather have these rules enforced with something like grumphp and php-cf-fixer, so it doesn't matter which editor people use.

[peter279k]

You're right. It can use the php-cs-fixer or StyleCI and let the command be the Composer script in composer.json.
Would you prefer which one to replace the .editorconfig?

Thanks.

[pascaldevink]

Thanks for the test additions, good spot with the phpunit upgrade.
I don't personally care much for coverage numbers, which is why I never added coveralls before, but now that you've implemented it I won't hold it back.

[peter279k]

Yes. The coverage numbers for someone that it's not the preference.
I integrate this because I think it's just a reference that let someone know the coverage numbers.