Unit Testing and Its Importance for Business Development

Regardless of its scale, stability and predictability are important for every IT project. Product availability and the achievement of your business goals depend on these factors.    

One of the criteria determining project stability is the correctness of writing code, as well as updating, optimizing and scaling it. To check whether they have performed these actions, programmers carry out unit testing, one of the many methods for checking code.  

This article we will analyze in detail and explain who writes them, how they are used and why they matter for business development.   

What is unit testing?

Unit tests are typical software tests designed to determine that individual components or modules (units) are fit for use.   

The goal of unit testing is to check each part of the program code for performance efficiency. These can include separate functions, modules, procedures or entities, including those introduced into coding for the first time.

Programmers write unit tests directly in the production code; therefore, it can be considered a separate stage of programming.  

Unit testing saves manual labour and eliminates human errors. This is especially important if you are working on a large project and it is difficult to check everything manually. Therefore, the larger the project, the more beneficial unit testing is.  

Essentially, automated unit tests save time. For example, if you are working on a large project where one module connected to five other modules must be updated, if you do not perform unit tests, you will have to manually check all six modules. With unit tests, the program will instantly show where the error occurred and/or what does not work.  

Note: Unit testing is an important stage in ensuring the reliability of the entire project (or IT product). It requires additional knowledge and experience. Therefore, unit tests are often written by experienced programmers, as junior programmers are often unable to write them.  

Best practices for unit tests   

You can follow different approaches when writing unit tests for specific projects:

  • if the development budget is limited, unit tests can ensure that the critical parts of the project, such as the payment module or similar components, work correctly. In fact, they should be controlled first;  
  • if the budget is insufficient for the entire project, tests can ensure not only individual parts, but 50-70% of the project, i.e. parts that can change frequently, related to other parts of the project or are simply important for business development;  
  • if the development is complex and has many internal dependencies, it is better to apply unit tests to the entire project. This will help you identify the problem areas in the codebase and take timely measures to fix the errors. This would be the ideal scenario.  

It should be noted that it is not necessary to write unit tests for the entire project immediately. They can be added while you are using the product, although it will take a little longer and turn out somewhat more expensive. Some startups do so, as they want to build a fast and cheap MVP, without the quality. However, large companies always write unit tests, and do so immediately. Many of them say that corporate development is impossible without unit testing.    

Most of our clients arrive with non-tested projects, which is why they have many errors that have actually accumulated over the years. Such an operational state complicates the work of the programming team. A lot of bugs accumulate in the project; it becomes more difficult to maintain the code; it takes more time to develop new functions, and as the project grows and develops, the number of new bugs and related costs only increase. In fact, the longer a project runs without unit testing, the higher the cost of maintaining it per each new line of code.   

Who writes unit tests?  

Programmers are responsible for writing unit tests; they write the code directly, which confirms that unit testing is an essential part of computer programming. For programmers, a unit test is not only a way to ensure product stability but also an additional opportunity to double-check their work. It is also an automated system, which significantly saves team resources in the future.

It should be noted that projects requiring 7-10 programmers can also have a specialist responsible for unit testing. Such a division of work increases the productivity of the Development Department and increases testing accuracy. Major corporations, which did not use unit tests in former projects, realize that it is necessary and, only after several years of project work, assign a separate programmer for unit testing. They come to understand the expediency of unit testing because of the growing number of bugs that inevitably accumulate due to old code or inconsistency issues. Practice shows that this is one of the main problems faced by our clients.    

Note: Do not confuse unit tests written by a programmer with autotests written using Selenium (automated testing framework) since they have a different work algorithm and even run in different parts of the project: unit tests are part of the Backend, and autotests work in Frontend, through a browser. Both unit tests and autotests are simultaneously used in projects; such a combination is close to ideal and allows you to complete the project with maximum quality, since these types of tests check different project parts and perform tasks that are not related to one another.  After all, unit testing verifies the logic mistakes in complex code in backend, and automated tests check the common mistakes in frontend. Both are working together.

Economic advantages  

Programmers, who develop software independently or as ordered by a client, sometimes refuse to run unit tests, saying that it will save time and resources for the Development Department. In practice, such savings promise higher costs in the future. If you save, let’s say, $100 on unit testing, later you might lose $1000 on bugs and their consequences (taking into account the scale of some projects, losses can amount to tens or even hundreds times more). 

This is due to the fact that with each update, it is necessary to test not only the new parts but also the entire project. Otherwise, it is impossible to make sure that the newly introduced parts have not affected the other parts.  

For example, when updating, the programmer removes one deprecated class or variable for the specific module being edited. But, a specialist may mistakenly not take into account or simply not know that the deleted variable is also used by other modules, which will inevitably impact their performance. If no unit tests or manual checks are done on the entire project, such problems can go unnoticed.  

Often, the manual testing is the most preferable, however, there are a certain number of limitations in manual testing: this method is suitable for working with small business sites but not with complex and large IT systems. So, any overlooked error or even code vulnerability can lead to serious problems and significant losses for the company, even more than possible savings.  In general, manual testing for large-scale projects will be more expensive than automation testing.

At one time, we worked on an interesting case that proves our point. Our client was a major American video production company. They had an online payment system, which suddenly stopped working. We discovered this defect after one of the customers complained. So, we added unit tests. In fact, as the payment module was not working, company customers simply could not process their payment, so they left the site. This is one of the most striking examples of a situation where economizing tests turns out to be a huge loss for the company.   

Unit testing is time-saving and enables you to immediately detect a problem. This means that any flaws and errors can be localized and eliminated in advance, before deploying to the live environment, and without disrupting software or website functionality.

It should be noted that writing unit tests is initially faster and easier than integrating them into an already debugged system afterwards, since unit tests require their own structure and it can take some time to learn the prepared code.   

Note: You do not need to limit yourself to unit tests. Different types of testing improve product quality. In addition, unit testing helps detect issues in your code, but will not help you to test interfaces.   

Can we do without unit tests?    

Many projects are initially built without unit tests. A company may want to save time and money or may prefer to write a test later. This is possible, but only in a number of cases when  

  • a simple promo website with multiple static HTML pages is being developed;  
  • an MVP (Minimum Viable Product) is being created for a new startup, and the budget and deadlines are more important than quality;  
  • a software demo is being created.   

We, at SECL Group, believe that it is impossible to do unit tests in all cases without damaging the actual IT product.   

What other types of testing can be used?    

Modern projects are so large and complex (containing many technologies) that sometimes a whole team and a whole set of tests are needed for testing purposes.  

In addition to unit tests, other methods can be used to test an IT product. Among the most common:  

  • Manual testing is a method used during the quality control process in the development of an IT product. It is performed without third-party software by modeling user actions.   
  • Autotesting is a method used during the quality control process in the development of an IT product. It is performed using software tools (applications) that simplify it and reduce labour costs.   

Other testing options can be used:  

  • load testing refers to checking the stability of the system under standard loads and determining the maximum allowable load;   
  • security testing is designed to assess the security of a system and its resistance to attacks, viruses and other third-party influences.   

This is a basic set of testing methods, and not a complete list. All of the tests listed above are used on large projects and particularly by our company. In fact, the set of tests depends on the specifics of the product being tested, as well as its complexity, customer requirements and the developer’s internal regulations.    

For example, our internal testing requirements include more than 400 checklists, which we adhere to, even if there are no requirements for testing. We believe that all systems require infinite testing!   


Unit testing is an important stage in the development and updating of an IT product and is aimed at improving its quality. Even though the programmer, who writes the testing code, must work a little longer, the unit test allows the developer to fully control the performance of the entire system, detect any errors in a timely manner and even localize them.   

Unit tests are very important for a company’s business development. It is an automated method, which means economizing resources while improving quality in the long term. Unit tests can help a company not to lose profits, customers or their loyalty.  


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