Blackbox Versus Whitebox Testing

What is Black Box testing?
In Black Box testing, a tester doesn’t have any information about the internal workings of the software system. Black Box testing is a high level of testing that focuses on the behaviour of the software. It includes testing from an external or end-user perspective. Black Box testing can be applied to virtually every level of software testing: Unit, Integration, System, and Acceptance.

What is White Box testing?
White Box testing is a testing technique which checks the internal functioning of the system. In this method, testing is based on coverage of code statements, branches, paths or conditions. White Box testing is considered as low-level testing. It is also called Glass Box, Transparent Box, Clear Box or Code Base testing. The White Box Testing method assumes that the path of the logic in a unit or program is known.

Black Box Testing versus White Box Testing:

Definition

• Black Box Testing – It is a testing approach which is used to test the software without the knowledge of the internal structure of a program or application.
• White Box Testing – It is a testing approach in which internal structure is known to the tester.

Alias

• Black Box Testing – It also knowns as Data-driven, Box testing, Data and Functional testing.
• White Box Testing – It is also called Structural testing, Clear Box testing, Code-based testing, or Glass Box testing.

The base of Testing

• Black Box Testing – Testing is based on external expectations; internal behaviour of the application is unknown.
• White Box Testing – Internal working is known, and the tester can test accordingly.

Usage

• Black Box Testing – This type of testing is ideal for higher levels of testing like System Testing, Acceptance testing.
• White Box Testing – Testing is best suited for a lower level of testing like Unit Testing, Integration testing.

Programming knowledge

• Black Box Testing – Programming knowledge is not needed to perform Black Box testing.
• White Box Testing – Programming knowledge is required to perform White Box testing.

Implementation of knowledge

• Black Box Testing – Implementation knowledge is not required doing Black Box testing.
• White Box Testing – Complete understanding needs to implement White Box testing.

Automation

• Black Box Testing – Test and programmer are dependent on each other, so it is tough to automate.
• White Box Testing – White Box testing is easy to automate.

Objective

• Black Box Testing – The main objective of this testing is to check the functionality of the system under test.
• White Box Testing – The main objective of White Box testing is done to check the quality of the code.

The basis for test cases

• Black Box Testing – Testing can start after preparing requirement specification document.
• White Box Testing – Testing can start after preparing for Detail design document.

Tested by

• Black Box Testing – Performed by the end user, developer, and tester.
• White Box Testing – Usually done by testers and developers.

Granularity

• Black Box Testing – Granularity is low.
• White Box Testing – Granularity is high.

Testing method

• Black Box Testing – It is based on a trial and error method.
• White Box Testing – Data domain and internal boundaries can be tested.

Time

• Black Box Testing – It is less exhausting and time-consuming.
• White Box Testing – Exhausting and time-consuming method.

Algorithm test

• Black Box Testing – Not the best method for algorithm testing.
• White Box Testing – Best suited for algorithm testing.

Code Access

• Black Box Testing – Code access is not required for Black Box Testing.
• White Box Testing – White box testing requires code access. Thereby, the code could be stolen if testing is outsourced.

Benefit

• Black Box Testing – Well suited and efficient for large code segments.
• White Box Testing – It allows removing the extra lines of code, which can bring in hidden defects.

Skill level

• Black Box Testing – Low skilled testers can test the application with no knowledge of the implementation of programming language or operating system.
• White Box Testing – Need an expert tester with vast experience to perform White Box testing.

Techniques

• Black Box Testing – Need an expert tester with vast experience to perform White Box testing. Equivalence partitioning divides input values into valid and invalid partitions and selecting corresponding values from each partition of the test data. Boundary value analysis. checks boundaries for input values.
• White Box Testing – Statement Coverage, Branch coverage, and Path coverage are White Box testing technique. Statement Coverage, Branch coverage, and Path coverage are White Box testing technique. Branch coverage validates whether each branch is executed at least once. Path coverage method tests all the paths of the program.

Drawbacks

• Black Box Testing – Update to automation test script is essential if you want to modify application frequently.
• White Box Testing – Automated test cases can become useless if the code base is rapidly changing.