What Is Code Unit Testing?

Featured article by Susan Melony, Independent Technology Author

When it comes to mapping out the DNA of your code, there is a lot that goes into it, including the testing phase. You want to be able to spot all possible issues and anomalies, and also find the root cause and make sure that gets to the right person.

You never want code that’s poor quality to be moved to production, and with that in mind, it’s important to understand all aspects of testing and quality control.

One aspect of software testing is called unit testing. Having an understanding of unit testing is essential for everyone in an organization that deals with software development in any way. The following is a breakdown of what unit testing is and what its implications are.

An Overview of Unit Testing

With unit testing, it’s a time during the overall software testing phase where you’re looking at specific units or individual components.

You want to make sure your software is going to work as it’s designed to and with unit testing, you’re taking the smallest component that you can test of any given part of the software.

Unit testing components will usually have one input and one output, or sometimes a few inputs and still only one output.

In procedural programming, the smallest unit could be any number of things, including a single procedure or function.

For object programming, the smallest unit might be a base class or a derived class.

What you want to find out with unit testing is where your algorithm may fail or where you could improve the quality of code as far as a particular function.

Unit tests are automated, and the tests themselves are frequently written and run by software developers.

When Does Unit Testing Happen?

While it can vary depending on the organization and its needs, usually unit testing is the first level of the software testing process. It will typically be done before Integration Testing. Integration testing is when units are tested together with one another to see where problems exist in their interactions.

There is an approach to unit testing called white box testing. White box testing means that the person testing the software chooses specific inputs to find the right outputs. During the unit testing phase, the person doing the testing will need a high level of understanding of programming and implementation.

These are high-level phases of testing and require the right tools and resources, and someone who is very skilled to do them.

How Much Of Your Code Should You Test?

There are differences of opinion among developers as to how much code should be tested at the unit level. For example, you’ll find developers who think you should perform unit tests on all of your code, while others think maybe anywhere from 50 to 80% should be tested.

What Are the Benefits of Unit Testing?

The primary benefit of performing unit tests is the ability to take each individual aspect of a program and make sure that it, as an individual part, is correctly written. This allows for the identification of possible problems early in development. Not only could unit testing be used early on to identify bugs, but also missing parts.

If you can find a bug before you actually begin coding or when the code is first written, you’re going to save time and money.

If you release a bug in your code, it can be expensive and damaging.

Other advantages of unit testing include:

– With the implementation of unit testing, you’re creating a more agile coding process. It’s much easier to make changes to software and add features if you aren’t changing existing code.

– With unit testing, you’re more likely to have quality code at the end. You’re finding those errors and problems early-on and working from the start to improve your code.

– If you do unit testing, you can not only find problems early, but you can also fix them without impacting the other areas of code.

– Unit testing gives developers time to really asses their code and think more clearly about what they want it to accomplish before it’s written in its entirety. You’re thinking in a more purposeful way when you’re doing unit testing.

Of course, keep in mind that testing isn’t going to identify every problem in code because not every execution path can be evaluated. Unit testing should be done as part of a larger and more comprehensive set of software testing strategies, particularly to ensure there aren’t unexpected behaviors that occur.