What is the white box testing?

White box testing tests a software's architecture, design, and programming techniques. It mainly focuses on verifying the flow of inputs and outputs within the application.

This testing is usually performed by developers. The code is visible to the tester, as opposed to in black box testingA testing type in which the tester doesn't know the inner details of the code. That is why it is also called open-box, clear-box, and glass box testing.

White-box testing focuses on the internal workings of an application. The term "white box" is used because it symbolizes the ability to see through the software's outer "box" into its internal structure (i.e., it is transparent).

Verification

The white testing technique attempts to find errors. It is used for the verification of the following categories, among others:

• Internal security holes

• Poorly structured or broken paths in the coding processes

• Expected output

• Testing of each instruction, object, and method individually

• The flow of specific input methods

• Working with conditional or nested loops

It includes testing a series of predefined inputs against desired or expected outputs, so the developer knows there is a bug when a specific input doesn't return the expected outcome.

Note: One of the most important goals of white-box testing is verifying the application's working flow.

Types of white box testing

White box testing encompasses several testing types that are used to evaluate code, conditions, or software packages. Some of them are listed below:

• Unit testing: Includes the testing of each unit or block of code.

• Testing for memory leaks: Checks the causes of slower-running apps.

• White box penetration testing: Attacks the code from several angles to expose security threats.

• Mutation testing: Checks the robustness and consistency of code.

• Integration testing: Checks the integration points between the components and external systems.

• Static code analysis: Identifies vulnerabilities or coding errors in static code using automation.

Techniques

One of the most commonly used techniques for white box testing is code coverage analysis. It eliminates gaps in a test case suiteA test suite allows us to categorize test cases in a way that they match our planning and analysis needs.. It identifies the areas of a code that are not tested previously, and doesn’t include them in the test case suite. Once the gaps are identified, we create test cases to check the untested parts of the code, thereby increasing the quality of the software product.

The following are a few testing techniques a box tester can use, where their work is the same as their names imply:

• Statement coverage

• Decision coverage

• Branch coverage

• Condition coverage

• Multiple condition coverage

• Finite state machine coverage

• Path coverage

• Control flow testing

• Data flow testing

Tools

Below is a list of popular white box testing tools:

• Parasoft

• Jtest EclEmma

• NUnit

• PyUnit

• HTMLUnit

• CppUnit

Advantages

There are many pros of white box testing. Some of them are listed below:

• Its optimization helps find hidden errors.

• It is widely used among other testing types as it covers the verification of the whole code.

• It can be done in earlier phases of software, thereby increasing the quality of software.

• Its test cases are easy to automate.

• It reduces communication overhead between testers and developers.

Disadvantages

A few disadvantages of white box testing are listed below:

• It is expensive.

• It is complex in terms of covering the whole code.

• It takes too much time for large-scale applications.

• It requires professional programmers with in-depth knowledge of programming.

Conclusion

A software application should undergo white box testing during its development after its code is written, and again after each alteration. White box testing can be pretty tricky. The application being tested has a lot to do with the complexity. A small application that performs a single, straightforward action can be white-box tested in minutes, whereas extensive programs might take months to test correctly.