10 Best Practices for Unit Testing in 2024

There are dozens of tests in developing software. To make sure software runs smoothly when it is deployed, multiple precautions are taken before it is launched. This means testing every aspect of the software on their own, as well as together.

Testing is done in each stage of development, and it is vital. Unit testing is a part of these tests and is one the most basic and fundamental of them all. In this test, the software will be seen as different units which will be tested one at a time.

What is Unit Testing?

Let’s take a look at the definition of unit testing. Unit means the smallest part of your software’s code which is repeatable, testable, and functional. Unit Testing is one of the primary tests of software and here we will be able to catch whether a bug is present in any unit before integrated testing is done. One thing to note in this case will be, that even when hundreds of testing is done, it does not guarantee that bugs won’t be found in the later stages of the testing.

For this type of testing, a white box test is usually used as the person who wrote the piece of code will know the function of the code best. This test will make sure you are aware of how your software is developing at the early stage of the development.

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Top 10 Best Practices for Unit Testing

Some procedures are to be followed when units are tested, and some work best for various tests. 10 of these are listed below.

1. Test Planning

All projects should always begin with planning and it is no different in this regard as well. Resources are limited so we cannot perform unit testing again and again. At the same time, equal resources cannot be poured into all the units. Thus, there needs to be a planning, and allocation of resources like money, time, and even labor for each unit which should be followed thoroughly to make sure the development can be done smoothly.

Advantages:

• A clear understanding of the needed budget and how to use it.
• A routine is formed when planning is made, this is much needed in group work
• Wise use of resources with less waste, leading to smooth development.

2. Readable Test

When coding or writing a test, one thing should be kept in mind this is documentation of the software you are testing and this information will be read again and again not only by you but even by others. Not everyone will be able to understand the code if it is too hard to comprehend, so it is best to write code in a form that is easily understandable by everyone. Make sure to have a clear and sound name for every test case as this is reflected upon the subject and nature of the test.

Advantages:

• When tests fail, it is easier to understand without debugging the codes.
• It is easier to maintain as product codes need to change in order to update in the test.
• Less misunderstanding is there between developers when the test is easier to read saving both time and energy.

3. Use AAA Pattern

AAA stands for Arrange, Act, and Assert. To make sure the test is easily readable it is best to use the AAA pattern. This is one of the most basic and frequently used structures by all developers. It is very important and makes testing much easier as it separates testing objectives, actions, and the results of the test. This divides the process of testing into three distinct parts which is why readability becomes better.

Advantages:

• The objective of testing becomes quite clear in Arrange.
• The tests are smoothly acted out in the process of Act.
• Results of the test will be given in Assert, making it clear with no confusion.

4. Deterministic Tests

Clear effort should be made to make sure tests are deterministic and avoid non-deterministic tests. A deterministic test is one where the test will either fail every time or pass all the time until and unless there is a change in the code. Non-deterministic tests will sometimes show that the test has passed and sometimes that it has failed even when there is no change in calculation. So, to be more accurate, deterministic tests are a must.

Advantages:

• Clear results will make solving the problems easier.
• No misunderstanding about the result of the test will be formed.
• Deterministic test results are accepted by all developers while they reject non-deterministic tests.

5. Logic in Tests

Logic like while, if, for, switch, etc. should be avoided in test writing as this makes the test less readable and the chances of bugs in the unit become higher. Test should focus on the results that are expected not on the implementation of the test. But, if using logic is unavoidable as it happens in some cases, it is best to split the test into different tests according to the needs.

Advantages:

• Avoiding logic in tests makes the test more readable and deterministic.
• Not using logic also makes sure there is no bug in the test.
• Readability makes functions of the test much simpler and easier to access.

6. Test Coverage

100% test coverage is usually not possible as all the bugs are not usually detectable and resources to cover all these tests are not feasible. The cost of the whole test will be much more than the manageable budget which is why planning is necessary. But with this being said, the coverage of the test should be as high as possible. More coverage means more problems can be detected and fixed, thus it is best to cover as many tests as possible.

Advantages:

• More tests mean more room for the detection of problems and solving them.
• The detection of problems in the unit stage is easier to fix than it is to fix at later stages.
• Solving more problems at the unit stage will make software development safer and smoother.

7. Automated Test

Automatic tests detect bugs in the early stages and give feedback while helping to keep in sight factors like how many tests have been run, performance, etc. Automatic testing is much quicker and easier to use as compared to manual testing, this is because automatic tests can run on their own without human interference saving much resources.

Advantages:

• Several tests can be run at the same time and continuously.
• Lesser need for human intervention which saves a lot of work.
• It also allows you to run multiple tests in a day as it performs quicker.

8. Write Tests as the Project Develops

Unit test is done at the early part of software development so it is better to write tests at this stage to understand the product code better. Moreover, fixing bugs as the development takes place will build a better foundation. When all the product development is done, some code might become codes that are not testable so it is best to write the test during development. This further gives us an idea of the future of the product.

Advantages:

• This gives us ideas about any problems we might face in the future.
• It familiarizes us with the test codes and product codes.
• Make sure that we avoid untestable code later down the line.

9. One Use Case per Unit Test

Use one case per unit test as this will make sure you are very clear about the expected outcome of the test. This will make sure you are able to know what the root problem is, this means managing the problem will also be easier and clearer. Although it might be a tedious job to write a case for each test, in the long run, it saves more time and at the same time gives a definitive result.

Advantages:

• Gives a definitive outcome, which makes understanding the results better.
• Can understand the problem easily as only one function is tested.
• Saves more time in the long run.

10. Test Documentation

Keeping various test documentation is needed and important, as test results are referred to again and again in each step of the software development. Further, when the software is deployed and some problems arise, the test results and process is needed in order to understand the problem and learn how to solve them.

Advantages:

• Tests can be reviewed by anyone for any purpose with documentation.
• A test is done in such a way it can be repeated to make sure of the result and a record is needed for this purpose.
• Documents can be archived and stored for future use.

Conclusion

A unit test is a necessity in software development while at the same time, repeated testing is encouraged. It is one process that is vital in making sure the software development will run smoothly and on deployment will have no problem. Thus, to make sure software does not have bugs to hinder its function, unit testing has to be performed. Now, performing unit testing can be done in many ways, following different steps and processes. But in order to make sure the software is safe and the tests are useful, these ten practices should be followed.

10 Best Practices for Unit Testing – FAQs

What are the different types of software testing?

There are various types of software testing, but unit testing is the foundation. It focuses on individual software components to ensure they function as intended. Other testing types include integration testing (combining units), system testing (entire system), and acceptance testing (user perspective).

Why is software testing important?

Software testing is crucial for delivering high-quality software. It helps identify and fix bugs early in development, preventing issues later on. This saves time, money, and improves user experience.

What are the benefits of unit testing?

Unit testing offers numerous benefits:

• Early Bug Detection: Catches bugs early, leading to faster and cheaper fixes.
• Improved Code Quality: Promotes well-structured, maintainable, and reliable code.
• Refactoring Confidence: Allows for code modifications without worrying about breaking functionality.
• Regression Prevention: Ensures changes don’t introduce new issues.