When we talk of software testing,
technical prowess in white box testing involves detecting vulnerabilities
in the logical structure of the code implementation. White box testing
is also referred to as glass box testing, clear box testing and structural
testing. It requires testers to create test cases to test the internal
path of programs. The tester should have strong programming skills to
choose the appropriate inputs for checking the accuracy of program logics
in order to get the required output. White box testing should ideally
be practiced in the following formats:

• Risk analysis should
  be done to streamline the testing process.
• All the testing
  activities to be performed should be mentioned in a test strategy to
  achieve testing goals.
• The whole testing
  process should be organized in the form of a test plan.
• To execute tests
  successfully, test environments should be prepared.
• Results should be
  communicated after the execution of the tests.
• A detailed report
  should be prepared.

Comprehensive White Box
Testing

In order to ensure that every
unit in the application is tested at least once, the following test
plans should be created:

Unit Testing: Performed during
development to check the functionality of a specific unit/statement.

Static and Dynamic Analysis:
While static analysis is finding any defect in the code without actually
executing it, in dynamic testing the output is evaluated through code
execution.

Statement Coverage: Tester
ensures that the execution is performed on each coding statement at
least once to diminish the scope of side effects.

Branch Coverage: Carried out
to ensure that the coding does not have any invalid branch that may
lead to unusual application behavior.

Security Testing: It ensures,
through various testing techniques, that only the authorized people
have access to the code.

Mutation Testing: After the
bugs or defects are fixed, the specific code is tested for its functionality
and validity over the previous code.

White Box Testing Techniques

Following are some the white
box testing techniques:

Data-Flow Analysis: In this
test, cases are developed keeping in mind the program data flow. This
also helps in understanding the program better.

Code-Based Fault Injection:
To check the behavior of the program, a piece of code is deliberately
injected into the code. This helps is exposing vulnerabilities, if any.

Abuse Cases: The code is viewed
from a hacker’s point of view to analyze its behavior.

Advantages of White Box Testing

In white box testing, the application is bound to get tested more effectively.
This is because the white box tester is aware of all the coding aspects
and can test the application through exact input or data. There may
be hidden defects caused by unnecessary coding lines that can be easily
removed through white box testing. Moreover, all the coding lines can
be optimized during white box testing, which alleviates the likelihood
of bugs.

Disadvantages of White Box Testing

White box testing increases the overall cost because only the person
who has in-depth knowledge of the internal logical structure can carry
out this testing. Moreover, the application may fail due to hidden errors
that can get ignored, since it is impossible to check the whole coding
to see which unit is faulty.