Gray box testing

Gray box testing sometimes called as Grey box testing. It is a combination of black box and white box testing features. In Gray box testing technique testing is carried out with a limited knowledge of the internal workings of an application. Testers have access to design documents and the database with this knowledge; testers can prepare better test data and test scenarios while preparing a test plan.

Below image illustrates the key differences between Black box, White box and Gray box testing techniques.

    Black box testing                    White box testing             Grey box Testing

Advantages:

• Testing is done from users point of view
• No need to depend up on source code

Disadvantages:

• Test coverage is limited
• Limited access to source code

Black box testing

Black box testing also called behavioral testing or input/output driven testing or closed box testing technique. Black box testing focuses on the functional requirements of the software. Black box testing is not an alternative to white box testing. Rather, it is a complementary approach with the intention of uncovering a different class of error than white box testing. Testers concentrate on what the software does; not how does it. It is performed by testers.

Black box testing helps to find errors in following categories:

• Incorrect functions
• Errors in data base
• Missing functions
• Interface errors

         Black box testing

Black box testing occurs throughout the software development and software testing life cycle.

Advantages:

• Source code knowledge and access is not required
• Test cases can be designed immediately after functional specifications are complete
• Testers can test the application having no knowledge programming language

Disadvantages:

• Insufficient testing
• Writing test cases is difficult