What is gray box testing?

In recent years the term gray box testing has appear into common usage. Gray box testing is a software testing procedure that uses an amalgamation of black box testing and white box testing techniques.

With gray box testing approach, Quality Assurance Engineer does have the knowledge of some of the internal structure of the application under test. In gray box testing, Quality Assurance Engineer creates some test cases for the internal mechanism of the application under test. For the rest of the test case, Quality Assurance Engineer uses a black box approach in applying inputs to the application under test and validates the outputs.