What is White Box Testing?
Testing the application using the internal source code is called White Box Testing.
It is done by a developer.
Types of White Box Testing include:
- Loop Testing
- Conditional Testing
- Path Testing
What is Black Box Testing?
Testing the functionality or GUI of an application without knowledge of the internal source code is called Black Box Testing.
There is no need for internal source code.
It is done by the testing team.
Types of Black Box Testing include:
- System Testing
- Acceptance Testing
What is Grey Box Testing?
Grey Box Testing is a software testing type in which the tester has only a partial understanding of the internal structure of the application.
The tester has limited information about the internal functionality and code.
The purpose is to search for and identify defects caused by:
- Improper code structure.
- Improper application use.
Black Box vs White Box vs Grey Box Testing
Black Box Testing
Knowledge of Code
- None
Performed By
- Testing Team
Focus
- Functionality / GUI
Example Types
- System Testing
- Acceptance Testing
White Box Testing
Knowledge of Code
- Full internal source code
Performed By
- Developer
Focus
- Internal logic (loops, conditions, paths)
Example Types
- Loop Testing
- Conditional Testing
- Path Testing
Grey Box Testing
Knowledge of Code
- Partial
Performed By
- Tester with limited code information
Focus
- Defects caused by improper code structure or improper application use
Verification vs Validation
Verification
Verification is done on documents.
It checks whether the product/system we are building is right.
It is static testing.
It checks whether we are following the right process.
The code is not executed.
It is performed using the software documentation.
Example
Google Maps — before starting, check whether it shows the correct path.
That is, checking whether it is right before we begin.
Validation
Validation is done on the software.
It checks whether the product/system we have developed is right.
It is dynamic testing.
It checks the software according to customer requirements.
Example
You start the car and go with the help of the map.
Here, checking whether the suggested route is actually right is validation.
Verification vs Validation
Verification
Done On
- Documents
Question
- Are we building the product right?
Type
- Static Testing
Code Executed?
- No
Validation
Done On
- Software
Question
- Have we built the right product?
Type
- Dynamic Testing
Code Executed?
- Yes
Code Coverage
Code coverage measures the amount of software (code) that is tested.
It falls under White Box Testing because it involves the code.
It helps us find the gap by identifying how much of the code is not tested.
When we find the gap, we increase our test coverage by giving more inputs so that more code is tested.
Path Coverage
We measure the number of paths in the program, or how many paths will be executed.
Path coverage is a White Box Testing technique.
The objective is to execute all possible independent paths in the program at least once.
It helps identify untested execution paths in the application.
Cyclomatic Complexity
Cyclomatic complexity is a testing metric used to measure the complexity of a software program.
It is a quantitative measure of the independent paths in the source code.
It can be calculated:
- Using control flow graphs.
- With respect to functions.
- Modules.
- Methods.
- Classes within a program.
It helps determine the minimum number of test cases required to achieve complete path coverage.
Higher cyclomatic complexity indicates more complex code and requires more test cases.
FAQs
1. What is the difference between Black Box Testing and White Box Testing?
Black Box Testing checks functionality or GUI without knowledge of the internal code and is done by the testing team.
White Box Testing uses the internal source code and is done by developers.
2. What is Grey Box Testing?
Testing with only a partial understanding of the application's internal structure.
It is aimed at finding defects caused by improper code structure or improper use of the application.
3. What is the difference between Verification and Validation?
Verification
Done on documents (Static Testing) to check whether we are building the product right.
Validation
Done on the software (Dynamic Testing) to check whether we built the right product according to customer requirements.
4. What is Code Coverage?
A White Box measure of how much of the code has been tested.
It reveals untested code so more inputs can be added to increase coverage.
5. What is Path Coverage?
A White Box technique whose objective is to execute all possible independent paths in the program at least once.
It helps identify untested execution paths.
6. What is Cyclomatic Complexity?
A metric measuring the number of independent paths in the source code.
It helps determine the minimum number of test cases needed for complete path coverage.
Higher complexity means more test cases.
7. Which testing types fall under Black Box Testing and White Box Testing?
Black Box Testing
- System Testing
- Acceptance Testing
White Box Testing
- Loop Testing
- Conditional Testing
- Path Testing
