What are low level and high level test cases? List out the differences?

IMPORTANCE OF TEST CASES
- Test cases are such an important part of software testing that they can’t be neglected.
- Test cases form the basis of any software testing methodology.
- After all, the efficiency of the software testing depends on how effective are the test cases developed for that particular type of software testing.
- The test cases are developed keeping in mind all the important aspects of the software testing.
- Aspects like the components of the application, its attributes, its features and functionality, kind of coverage needed, aim of the testing methodology and requirements of the software system or application.
- One test case tests only one feature, functionality or aspect of the software system or application.
- It is necessary that the test case is implemented properly and according to the specifications.
- If the test case is not implemented properly then it makes no sense of testing no matter how effective and efficient is the test case.

LOW LEVEL & HIGH LEVEL TEST CASES
There are basically two types of test cases about whom we shall be discussing in this article. These are namely low level test cases and high level test cases.

DIFFERENCES BETWEEN LOW LEVEL & HIGH LEVEL TEST CASES

DIFFERENCE #1:
- Low level test cases are developed pertaining to the low level bugs in a software system or application.
- On the other hand high level test cases are concerned with the bugs of high levels.
- Wherever a low level bug is suspected in the program code a low level test case is used for testing and wherever a high level bug persists, correspondingly a high level test case is used.

DIFFERENCE #2:
- High level test cases are developed for testing the major functionalities and features in a software system or application rather than just testing high level bugs.
- Major functionality may include display, update data base, retrieval and so on. They can be rather called test cases related to functionality.
- The low level test cases can be appropriately called test cases related to the user interfaces as they are very effective in testing the application’s user interfaces besides low level bugs.

DIFFERENCE #3:
- While carrying out the software testing, the high level test cases based on the requirements test the corresponding functionality.
- Requirements need to be identified properly so that there is no faltering while performing the test. This is called high level testing.
- Similarly testing carried out using low level test cases is called low level testing and is employed to test the software system or application at the micro level i.e., the expected outcome and the actual outcome.

DIFFERENCE #4:
- Low level test cases include the following test cases:
(a) For integration testing
(b) For unit testing
- On the other hand, the high level test cases are further sub divided into the following test cases:
(a) Test cases for system testing
(b) Test cases for functional testing and
(c) Test cases for acceptance testing.

DIFFERENCE #5:
- The high level test cases are able to provide better test coverage.
- They don’t focus much on the features and functionality but only to the extent that they should work properly and well in accordance with each other.
- The low level test cases are focused up on each and every minor detail of the program code.
- The program is tested in depth.
- Therefore we can say that the low level testing involves more detailed work than the high level testing.

DIFFERENCE #6:
- Low level testing and high level testing belong to the category of white box testing and black box testing respectively.