Unit testing is the part of the software development process where each unit of code is analyzed to make sure it is functioning properly. Writing a good unit test is critical to writing good software, but the best practices for unit testing aren’t very obvious. As a result, even veteran coders may struggle to write a useful test that adds value to the project.
What a Unit Test Is, and What it Isn’t
A unit test shouldn’t be used to detect bugs or regressions. Instead, a good unit test should only be used to design a single component. If other parts of the codebase change, then your unit test will not fail. If they do, then your test was not designed properly. To test the functionality of the program as a whole, manual testing or automated integration testing is the preferred method.
Designing a Good Unit Test
So, we can use our newfound knowledge of unit tests to start writing them. Every good unit test should have a few things:
· Make Each Test Independent
In most projects, all the tests are run at the same time. So, each test needs to be able to run independent of the others. Remember, you are only testing one particular piece of code through each unit test. An added benefit of creating separate test cases is that you can retest single cases quickly without running the whole program again.
· One Test Per Case
Each unit test should only focus on one method or class. Again, this is for simplicity’s sake; if your tests analyze a group of code units, a change to one of the units can cause failures to pop up everywhere.
· Use One Assert Method Per Test
Do you notice a pattern here? You should always make your unit tests as simple as possible. Don’t complicate the analysis by testing for too many things at once. By limiting the number of asserts that go into a test, you’ll make it easier to find the root cause of the failure.
· Code Coverage
Your unit tests should verify the majority of your code. Generally, a code coverage of 80% and above means that your test scripts are thorough.
· Consistent Results
Each of your unit tests should return the same result every time they are run. If your tests are displaying different outcomes each time, then there is instability in the code and you should revise it.
Some software specialists will argue that any unit test is better than none. However, we believe that test scripts written improperly can be a huge burden on you team; so, it’s important to get them right. Structuring your tests according to the above principles will ensure that your development process stays agile and will decrease the amount of time-consuming code changes.
If you have any further questions, give the Software Specialists a call. We’re always ready to help your team create the best solutions to your IT problems.