Usually, the test cases are written by the developers themselves and are used to make sure the core behavior of the software is not impacted. These test cases act as the initial gating and are usually the first ones the developer tests after making incremental changes to the software.

In an automation infrastructure, the unit tests are usually performed to test the basic functionality of the software before running the extensive QA test cases.

Example:

Let’s take the example of a health care software application, that is used by Doctors and Patients to log appointments, communicate with each other, share health records etc.,

The unit tests usually cover the appointment system, the ability of the doctors to look at their upcoming appointments and past appointments with patients, the basic messaging between doctors and patients, patients’ health records etc.,

Suppose, a developer makes changes let’s say to support secure messaging between doctors and patients, to perform basic testing before these changes are giving to QA team for further testing, she runs the above mentioned unit tests to make sure the basic functionality of the software is intact.

Conclusion:

Unit testing, constitutes a very important component of Quality assurance within a software company, often serving as the first step in identifying issues with incremental changes to the software.