Fix Calls to count()

[bbatsche]

Description

Add logic and checks to avoid passing null to count() and make sure that any classes with a public count() method implement Countable interface.

Fixed Issues (if relevant)

1. Warning: count(): Parameter must be an array or an object that implements Countable #7: Warning: count(): Parameter must be an array or an object that implements Countable

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[buskamuza]

There are still failures with count().
See:

• https://travis-ci.org/magento-engcom/php-7.2-support/jobs/355658287
• https://travis-ci.org/magento-engcom/php-7.2-support/jobs/355658288
• https://travis-ci.org/magento-engcom/php-7.2-support/jobs/355658291
• https://travis-ci.org/magento-engcom/php-7.2-support/jobs/355658292
• https://travis-ci.org/magento-engcom/php-7.2-support/jobs/355658293

[buskamuza]

Please run builds and fix issues with count()

[bbatsche]

@joanhe Is there a reason for this? I feel like it definitely does not belong here

[joanhe]

@bbatsche This is to resolve test failure in php 7.2.
session_id(): Cannot change session id when headers already sent in

[bbatsche]

Maybe try adding this right above the call that's failing, or somewhere in one of the setUp*() methods. No code or function calls should be in this file and not inside of the class itself.

[joanhe]

This is the only place works.