White box testing is a form of application testing that provides the tester with complete knowledge of the application being tested, including access to source code and design documents.

Test engineers should not be involved in white box testing because:

• if they spend time in fixing the bug, they lose time to catch some more other defects in the software
• fixing a defect might break a lot of other  Thus, testers should always identify defects and developers should always be involved in fixing defects.

WBT is following types:

• Loop Testing
• Path Testing
• condition testing
• WBT from memory point of view
• WBT from performance point of view