1) Black Box Testing
2) White Box Testing
3) Grey Box Testing
Black Box Testing:
Black Box Testing is also known as Functional Testing. It is a technique whereby the internal workings of the item being tested are not known by the tester. The tester only knows the inputs and what the expected outcomes should be and not how the program arrives at those outputs. The tester does not ever examine the programming code and does not need any further knowledge of the program other than its specifications.
Advantages of Black Box Testing
- Tester can be non-technical.
- Used to verify contradictions in actual system and the specifications.
- Test cases can be designed as soon as the functional specifications are complete.
Disadvantage of Black Box Testing
- The test inputs needs to be from large sample space.
- It is difficult to identify all possible inputs in limited testing time. So writing test cases is slow and difficult
- Chances of having unidentified paths during this testing
White Box Testing:
White box testing involves looking at the structure of the core. When you know the internal structure of a product, test can be conducted to ensure that the internal operations performed according to the specification. And all internal components have been adequately exercised.
Advantages of White Box Testing
- More code coverage.
- It can start in the early phase along with software development hence more error can be found earlier during the process of development.
- As the knowledge of internal coding structure is prerequisite, it becomes very easy to find out which type of input/data can help in testing the application effectively.
- It helps in optimizing the code and giving more stable build.
- It helps in removing the extra lines of code, which can bring in hidden defects.
Disadvantages of White Box Testing
- As the Knowledge of code and internal structure is a prerequisite, a skilled tester is needed to carry out this type of testing, which increases the cost.
- It is nearly impossible to look into every bit of code to find out hidden errors, which may create problems, resulting in failure of the application.
- There is no way to detect missing paths and data-sensitive errors.
Grey Box Testing:
Gray box testing is a combination of black box testing and white box testing. Gray box testing is not black box testing, because the tester does know some of the internal workings of the software under test. In gray box testing, the tester applies a limited number of test cases to the internal workings of the software under test. In the remaining part of the gray box testing, one takes a black box approach in applying inputs to the software under test and observing the outputs.
Gray box testing is a powerful idea. The concept is simple; if one knows something about how the product works on the inside, one can test it better, even from the outside. Gray box testing is not to be confused with white box testing; i.e. a testing approach that attempts to cover the internals of the product in detail. Gray box testing is a testing strategy based partly on internals. The testing approach is known as gray box testing, when one does have some knowledge, but not the full knowledge of the internals of the product one is testing.
In gray box testing, just as in black box testing, you test from outside of a product, just as you do with block box, but you make better-informed testing choices because you're better informed; because you know how the underlying software components operate and interact.
