Any time a feature is added or improved, an application’s code is in danger. There’s no escaping it, unfortunately: Any time a developer touches an existing piece of code, s/he introduces the possibility of breakage and new defects. This is especially true, and most common, in the areas where new code meets old.
There’s no substitute for skilled developers. They’re the powerhouse behind the product. The chief creation officers. They’re tasked with engineering your product’s architecture, coding the new features that will captivate your users and expanding the market reach of your organization. But, as humans are used to, developers also make mistakes in their pursuit of greatness.
Whether you're pursuing onsite or offshore QA, functional testing is an essential component of any test suite. It shows how effectively an application or system performs as a whole. Functional testing ensures that the customer's requirements will be met upon delivery, so the inputs are typically the specific business requirements.