White Box Testing (WBT) is also known as Code-Based Testing or Structural Testing. White box testing is the software testing method in which internal structure is being known to tester who is going to test the software. The White-box testing is one of the best method to find out the errors in the software application in early stage of software development life cycle.
White box testing involves the testing by looking at the internal structure of the code & when you completely aware of the internal structure of the code then you can run your test cases & check whether the system meet requirements mentioned in the specification document. Based on derived test cases the user exercised the test cases by giving the input to the system & checking for expected outputs with actual output. In this is testing method user has to go beyond the user interface to find the correctness of the system.