Define testing. Explain White Box Testing and Black Box Testing in detail.

Testing in software development refers to the process of executing a program or application with the intent of finding software bugs. It can also be stated as the process of validating and verifying that a software program or application or product meets the business and technical requirements that guided its design and development.

White Box Testing, also known as Clear Box Testing, Open Box Testing, Glass Box Testing, Transparent Box Testing, Code-Based Testing or Structural Testing, is a software testing method in which the internal structure/design/implementation of the item being tested is known to the tester. The tester chooses inputs to exercise paths through the code and determines the appropriate outputs.

In white box testing, an internal perspective of the system, as well as programming skills, are used to design test cases. The tester looks at the code to identify possible points of failure. This method is named so because it allows the tester to see through the software's "box", which refers to the code of the application.

Black Box Testing, also known as Behavioral Testing, is a software testing method in which the internal structure/design/implementation of the item being tested is not known to the tester. These tests can be functional or non-functional, though usually functional.

In black box testing, the tester interacts with the system's user interface by providing inputs and examining outputs without knowing how and where the inputs are worked upon. The tester is oblivious to the system architecture and does not have access to the source code. Typically, while performing a black box test, a tester will interact with the system's user interface by providing inputs and examining outputs without knowing how and where the inputs are worked upon.