White Box Testing
Tags: Quality Assurance, White Box Testing, Test, QA, Testing

White-box testing is the use of these techniques as guidelines to create an error-free environment by examining all code. These white-box testing techniques are the building blocks of white-box testing, whose essence is the careful testing of the application at the source code level to reduce hidden errors later on.

These different techniques exercise every visible path of the source code to minimize errors and create an error-free environment. The whole point of white-box testing is the ability to know which line of the code is being executed and being able to identify what the correct output should be.

Levels

Unit testing. White-box testing is done during unit testing to ensure that the code is working as intended before integration happens with previously tested code. White-box testing during unit testing potentially catches many defects early on and aids in addressing defects that happen later on after the code is integrated with the rest of the application and therefore reduces the impacts of errors later in development. Integration testing. White-box testing at this level is written to test the interactions of interfaces with each other. The unit-level testing made sure that each code was tested and working accordingly in an isolated environment and integration examines the correctness of the behavior in an open environment through the use of white-box testing for any interactions of interfaces that are known to the programmer. Regression testing. White-box testing during regression testing is the use of recycled white-box test cases at the unit and integration testing levels.

What do you verify in White Box Testing?

White box testing involves the testing of the software code for the following:

Internal security holes

Broken or poorly structured paths in the coding processes

The flow of specific inputs through the code

Expected output

The functionality of conditional loops

Testing of each statement, object, and function on an individual basis

The testing can be done at system, integration, and unit levels of software development. One of the basic goals of white-box testing is to verify a working flow for an application. It involves testing a series of predefined inputs against expected or desired outputs so that when a specific input does not result in the expected output, you have encountered a bug.

Basic procedure

White-box testing’s basic procedures require the tester to have an in-depth knowledge of the source code being tested. The programmer must have a deep understanding of the application to know what kinds of test cases to create so that every visible path is exercised for testing. Once the source code is understood then the source code can be analyzed for test cases to be created. The following are the three basic steps that white-box testing takes in order to create test cases:

Input involves different types of requirements, functional specifications, detailed designing of documents, proper source code, and security specifications. This is the preparation stage of white-box testing to lay out all of the basic information. Processing involves performing risk analysis to guide the whole testing process, proper test plan, execute test cases, and communicate results. This is the phase of building test cases to make sure they thoroughly test the application the given results are recorded accordingly. Output involves preparing a final report that encompasses all of the above preparations and results.

Advantages

White-box testing is one of the two biggest testing methods used today. It has several major advantages:

The side effects of having knowledge of the source code are beneficial to thorough testing. Optimization of code becomes easy as inconspicuous bottlenecks are exposed. Gives the programmer introspection because developers carefully describe any new implementation. Provides traceability of tests from the source, thereby allowing future changes to the source to be easily captured in the newly added or modified tests. Easy to automate. Provides clear, engineering-based rules for when to stop testing.

Disadvantages

Although white-box testing has great advantages, it is not perfect and contains some disadvantages: