UnitTests for this SDK

[xiaohuilam]

Background story

We need to know if any API server upgrades or SDK upgrades will turn any features down or not with a testing service automatically.

Documents & Environment maybe helpeful

• https://sslcomapi.docs.apiary.io - SSL.com's API Document
• https://sandbox.ssl.com - SSL.com's Sandbox Environment
• https://laravel.com/docs/8.x/testing - Laravel Testing Document