Software testing refers to the systematic process of verifying that the resulting product performs as expected and ensuring that it does not contain any unwelcome surprises after delivery.
Software testing costs significantly less than finding a critical bug and fixing it after the product has shipped. However, the loss of customer satisfaction and loyalty is the highest cost of finding an error after the product has shipped.
Your customers could turn to a competitor in no time, and the story would stop abruptly.
The process of developing and testing software is essential.
It ensures quality, reliability and reduces risk. Additionally, thorough testing ensures effective performance and satisfied consumers, which translates into a successful business.
Software products can be evaluated against a variety of criteria and in a variety of ways.
At a fundamental level, however, one can think about the intended functionality of the software, i.e. whether it behaves as expected.
White box testing is a broader type of product testing. Here, you're testing more than functionality. Compared to the black box, the box is now translucent, or rather, it is now white. Thus, you can observe the inner workings of the product.
Show all statements, conditional loops, input streams, etc.
Therefore, you will need an experienced programmer or a testing specialist who is proficient in programming languages and white-box testing coding procedures. This article will focus on white box testing.
What is white box testing?
White box testing is a technique that allows testers to examine and verify the inner workings of a software system, including code, infrastructure, and connections to external systems.
White-box testing is an integral part of the automated build process of contemporary continuous integration/continuous delivery (CI/CD) software development pipelines.
Static Application Security Testing (SAST) often refers to white-box testing, a method that automatically examines source code or binaries and provides feedback on potential vulnerabilities and defects.
What does white box testing focus on?
White box testing can address any of the following issues with the application source code:
Security Holes and Vulnerabilities
A security hole is a program component that makes an application vulnerable to attack. For example, not protecting your application from injection attacks can leave a security hole in your program that an attacker could one day exploit to compromise client data.
White-box testing determines whether an application is programmed using security best practices and whether the code is vulnerable to known security threats and attacks.
Check for broken/poorly structured programming paths
There are certain coding standards that, if not followed, may not result in bugs, but may lead to unexpected behavior in some cases.
Furthermore, coding constructs such as conditions can lead to unpredictable results if left unchecked or if the programmer does not check all possible values of the condition.
White-box testing helps reveal incomplete and erroneous program structures, and finds redundant, flawed, or inefficient conditional logic.
expected output
This requires evaluating all possible inputs to a function to determine whether it always produces the expected result.
cycle test
A program will always fail if the loop construct is not written correctly and causes it to run into an infinite loop.
Since nested loops can quickly become an unmanageable maze of code, it's best to avoid them whenever possible in favor of more straightforward constructs.
White-box testing evaluates the efficiency, conditional logic, and correct handling of local and global variables in individual loops, loops in series, and nested loops.
Data Flow Testing (DFT)
This is the process of following variables and their values as they flow through your code to identify variables that were initialized incorrectly, declared but never used, or incorrectly modified.
To determine whether there is a competing variable name or whether a program construct has incorrectly changed the variable's value, it is recommended to trace the variable's lifetime from declaration to destruction.
Verify expected results
One of the most critical aspects of testing is determining whether the expected results were achieved.
White-box testing is performed to ensure that the expected results of a software program are achieved.
Validate every statement and function call
White box testing requires the verification of each statement within a function to ensure the integrity of the program.
Types of white box testing
The two most popular forms of white box testing are unit testing and integration testing.
1. Unit testing
In unit testing, an application is viewed as a collection of components or modules. Therefore, the control data, methods and processes of each module are independently verified. Typically, developers write automated tests to confirm that application components meet design requirements.
Programming style is a key determinant of unit components.
For example, in object-oriented style, a unit becomes a class and its interface. Execution, operation and maintenance, and mutation tests are all kinds of unit tests.
2. Integrated assessment
During integration testing, many related individual units or modules are checked as a group. It evaluates the degree to which constituent units meet functional criteria and identifies any deficiencies in the interactions between the various elements.
Integration testing is subdivided into top-down, bottom-up, and hybrid approaches.
Other forms of white box testing include:
mutation test
This form of unit testing verifies the resiliency and consistency of the code by designing the tests, making small random changes to the code, and determining whether the tests still pass.
White Box Penetration Testing
In this type of white-box testing, an ethical hacker appears as a knowledgeable insider and tries to use his extensive knowledge of the code and environment to attack the application.
static code analysis
Automatically discover vulnerabilities or coding flaws in static code using predetermined patterns or machine learning.
Steps to perform white box testing
White box testing requires the tester to perform multiple tasks.
1. Determine what must be tested
White-box testing encourages checking every component of the selected instance. Therefore, a lower number of identification pieces is desirable.
Existing flaws become apparent after these are tested.
These features and components are tested repeatedly to ensure they work as intended. Extracts and evaluates widgets, and extracts the next component when the goal is met.
The energy efficiency of the test is also important, meaning that the energy consumed is directly proportional to the results obtained.
2. Organization Flowchart
A flowchart describes all possible and conceivable paths. These paths may correspond to any function, module or component. Execute it to determine the scope of the test.
3. Develop test cases for all paths
After mapping the various paths, create test cases for each possible path. After the test cases are created, they are executed.
4. Execution
This is the test execution phase, where the test cases are executed. Then, the execution phase can be repeated to confirm the test results.
white box testing technique
A major goal of white-box testing is to cover the source code as thoroughly as possible.
Code coverage analysis is a popular white-box testing method.
Code coverage, often called test coverage, is a metric that indicates how many statements or lines of code have been executed.
Using concepts such as statement coverage, branch coverage, and path coverage, it is possible to determine how much application logic was run and tested by the unit test suite.
We discuss these concepts further below:
Report Coverage
As the name suggests, statement coverage aims to evaluate the maximum number of executable statements across modules or functions.
This white-box testing technique ensures that all executable code statements are executed and tested at least once. For example, if there are multiple conditions in a code block, each for a given range of input, the test should evaluate each capacity of the input to confirm that all lines of code have executed.
Statement coverage helps identify new statements, unwanted branches, missing statements referenced by parts of the code, and dead code left over from previous versions.
Decision Coverage/Branch Coverage
Branch coverage divides the code into branches of conditional logic and ensures unit tests cover each branch.
This coverage technique maximizes the testing of each branch, such as if statements or loops.
path coverage
Path coverage pertains to linearly independent code paths. In the path coverage technique, testers write unit tests to execute as many paths of program control flow as possible. The purpose is to detect broken, duplicated or inefficient paths.
multiple coverage
Test every combination of potential outcomes of a condition or decision statement.
Other code coverage methods include finite state machine, path, control flow, and data flow coverage.
Advantages of white box testing
In addition to the benefits provided by testing, white box testing also provides:
- Simple script automation for testing.
- Since the code checks one statement at a time, it is greatly optimized.
- Extremely exhaustive testing covering all pathways.
- Unit testing can start relatively early in the application's lifecycle, minimizing the chance of bugs later in the lifecycle.
Disadvantages of white box testing
Like all other concepts, there are; white box testing has its drawbacks.
Here are some prominent disadvantages:
- Compared to other types of testing, white box testing is a complex, time-consuming and expensive endeavor.
- For white-box testing, additional high-quality resources are required.
- This can be expensive.
- Often, tests are not exhaustive; therefore, they may contain bugs.
- Testing requires experienced resources as it involves technical understanding.