Unit Testing vs Integration Testing

The Software Development Life Cycle(SDLC), requires the execution of the specific testing activities, after the completion of each level of the development, in order to minimize the percentage of defects in the final product. These testing activities includes, two of the necessary and significant testing techniques, i.e., unit testing and integration testing.

Unit testing is a type of testing activity, which validates the correct and desired working of the developed components or units of the software product, whereas Integration testing is done on integrated units, to ensure the proper interaction, compatibility, reliability among the components.

Let us go through the points, which differs the unit testing from the integration testing.

Sl.No. Unit Testing Integration Testing
1. It evaluates the each component or unit of the software product. It examines the proper working, interface and reliability, after the integration of the modules, and along with the external interfaces and system.
2. Considers each component, as a single system. Integrated components are seen as a single system.
3. The chief purpose is to check fitness and working of the each unit, for their further use. The motive is to check the reliable working of each unit or module, after the integration process.
4. First level of the testing, in the development life cycle. It starts, with the completion of the unit testing phase and after the integration of the components.
5. The scope of the testing, is limited to a particular unit, under the test. The scope of the testing is wider in comparison to unit testing, as it covers two or more than two modules, or may be whole system.
6. It has no further types. It, generally includes two approaches.
  • Bottom up integration testing
  • Top down integration testing
7. It is also known by the name of the component testing. It has no other name.
8. It does not deals with the database. It involves the usage of the database.
9. Detailing of the code, is covered under the test. Integration structure of the system, is perceived under the test.
10. It is performed at the coding level. Usually, done at the communication level.
11. It does not support any type of external dependencies. It involves the dependencies and interaction with the external system.
12. Unit tests are faster, to execute. Integration tests, are comparatively slower the unit tests.
13. It is carried out with the help of the reusable test cases. Generally, it is carried out with the help of the stubs and drivers.
14. It is a type of White Box testing. It is the form of, both black box testing and white box testing.
15. Mostly, developers perform the task of unit testing. Testers, along with the integration team are being assigned, the work of integration testing. Developers may also takes part in the testing.