Advantages and Disadvantages of White Box Testing

Advantages of White box testing are:
i) As the knowledge of internal coding structure is prerequisite, it becomes very easy to find out which type of input/data can help in testing the application effectively.
ii) The other advantage of white box testing is that it helps in optimizing the code
iii) It helps in removing the extra lines of code, which can bring in hidden defects.
iv) Forces test developer to reason carefully about implementation

White-box testing is an important method for the early detection of errors during software development. In this process test case
generation plays a crucial role, defining appropriate and error-sensitive test data. White-box testing strategies include designing tests such that every line of source code is executed at least once, or requiring every function to be individually tested. Code coverage is a significant benefit provided by white box testing. It is much easier to determine if you’ve looked at all functions, libraries, etc, when you know what they all are.

Disadvantages of white box testing are:
i) As knowledge of code and internal structure is a prerequisite, a skilled tester is needed to carry out this type of testing, which increases the cost.
ii) And it is nearly impossible to look into every bit of code to find out hidden errors, which may create problems, resulting in failure of the application.
iii) Not looking at the code in a runtime environment. That’s important for a number of reasons. Exploitation of a vulnerability is dependent upon all aspects of the platform being targeted and source code is just of those components. The underlying operating system, the backend database being used, third party security tools, dependent libraries, etc. must all be taken into account when determining exploitability. A source code review is not able to take these factors into account.
iv) Very few white-box tests can be done without modifying the program, changing values to force different execution paths, or to generate a full range of inputs to test a particular function.
v) Miss cases omitted in the code