Software Testing Can be Classified as Follows:

Functional testing is a software testing done to verify if an application performs its functions correctly (namely correctness of functional requirements). It is known as a black-box testing technique, however, white-box testing approach can be also useful for determining the functionality of a software app (checking the capability of the product to provide all the functionality which meets implied and stated needs while the app is used in certain environment.  

Perspectives of Functional Testing:

1. Requirement-based testing
2. Business-process-based testing  

Offshore software testing services are more and more often used for testing functionality of different software products. They have earned the trust of the customers because the outsourcers honestly do their job, namely, execute prompt, reliable and economical testing. Their motto is to gain continually higher levels of customer satisfaction.

Non-functional testing is a testing that focuses on examining those features of an application which have nothing to do with functionality: efficiency, reliability, maintainability, compatibility, performance, security, usability and portability.  

By the way, when you urgently need to check if your product is functionally correct or not, you can use functional testing service. In the course of this verification, the problems with the software will be identified and removed.

Types of Non-Functional Testing:

Volume testing is mainly aimed at evaluating the performance of a system by subjecting it to specified amount of data. It is also known as a flood testing. The process aims to determine the execution period (time spent for completing the activity) and some users (the ability of the app to handle the inquiries from simultaneous connectors.

Load testing is one of the most important steps in assessing the performance of a system. It allows checking if the product is working correctly under varying loads. This testing is automated. Load testing service will help you understand if your app is capable of handling the high demand.

Stress testing makes it possible to determine the stability of the application by testing it beyond the standard operational capacity and if it can recover after extremely heavy loads. This process is a part of performance testing and under certain circumstances may indicate of the performance decrement.