Unit testing: leave no chance for bugs in your app!

Quality assurance or software testing or ‘checking for bugs’ is one of the final and extremely important stages in software development. Saving company’s or startup’s budget on testing makes absolutely no sense… In addition to essentially reducing the chances to gain the customers or to maintain the existing number of them, you will spend a lot more money on fixing bugs if they are detected! This is why nowadays companies often dole out up to 40% of their budget on testing!

In our blog we have already touched on this topic and not once (see the articles Does Your Startup Need Software Testing? and Automated Testing and QA: basics, pros and cons). This time we are going to tell you about one of the simplest, but at the same time most advanced methods of software testing — unit testing. Available only to programmers or testers with programming skills, it runs fast and guards your app from any kind of bugs sufficiently. Along with this, it can be launched not only after the code is done, but right in the process of writing it! Sounds interesting? — Then make yourself comfortable and read this article all the way through…

Unit testing: definition

First of all, let us cast light on why this kind of testing is called “unit-testing”. So, what the units are? Simply put, a unit is the smallest part of a program that can be tested and is responsible for one of the program’s functions. For instance, the function of linking clients’ personal information to a hotel room (for hotel booking service) or various calculator functions. Units cannot be seen in the end product: they are the parts of a program, generated by dividing it into elements. Developers write a special code to get their code divided into those parts, and then test each part (element) separately.

How it works

Unit testing is a type of automatic testing and can perform abundance of tests at a time, doing it fast and free from any human errors. It requires programming skills and not every tester has them (in many cases, testers don’t have programming skills), still the structure of a unit test is very simple. What is unit testing if we look at this process from the inside? — It is sending certain inputs to the core of the software and then evaluating the result. The standard structure of a unit test is as follows:

• Inputs (‘Given’);
• Code to test (‘It’);
• Results evaluation (‘Should’).

Through the ‘Given’ segment the inputs are given to the program part which is tested (certain feature). The ‘It’ part of the unit testing structure is dedicated to the function which is to be tested. The results are evaluated and the test comes to its ‘conclusion’ (fails or passes) in the ‘Should’ section.

What unit testing is used for?

As it has already been mentioned, unit-testing is a kind of automatic testing, which is performed not by a human, but a code written by a developer/tester with programming skills. In contrast to manual testing, it is free from possible ‘human errors’ and can be performed not only after a program release, but right in the process of coding. Basically, unit-testing is the very first level of testing, the foundation for the other testing levels. The software test plan, i.e. the hierarchy of these testing levels is as follows:

Being performed automatically and dealing with small parts of a program code, unit tests are operated fast. Bugs can be found early and easily, and this prevents big money expenditures on bugs’ fixing after a program’s release. Unit testing also saves much time, which otherwise is usually spent on searching reasons for why the bugs emerged.

Having a reliable, bug-free code is a great advantage for any project or company, as it allows delivering a quality product, and therefore gaining new clients. But for large projects and enterprises preventing and eliminating bugs at the early stage is not just important — it is of the vital necessity! So using unit testing plays the great role in providing a truly remarkable and quality product to customers. It can be recommended to use for any projects, but especially — for the large ones.

Pros and cons

Everything in this world is of ‘two sides of the same coin’. Unit testing provides obvious advantages in terms of the end result, and still it has some vexed points…

But first, let us direct our attention to the benefits of using unit testing in a product development.

Benefits:

• It makes the code more reliable and changes to it introduced more confidently and without unintended side effects. If unit tests are of good quality and are let off after each change to the code, all possible defects would be detected promptly and easily;
• Codes become more reusable (because they become modular);
• The development goes faster. It is quite obvious: detecting and fixing bugs found during unit testing takes much less time and effort than while the higher levels of testing;
• It is about money saving too. Detecting and fixing bugs while unit testing is cheaper as well, — as compared to debugging at the higher levels;
• Debugging easiness. It is much easier to fix bugs on the unit testing level, than on the higher ones. Why? — Because unit testing works only with the latest changes to the code (brought after the initial or latest unit testing). When testing at higher levels, all the changes made over all the period of the code’s life are to be checked;

And here we come to the disadvantages of the method… To be honest, the ‘positive’ side of the ‘coin’ outweigh the ‘negative’ one essentially, still, in some situations there can be some minuses from using this testing method.

Risks:

• It can take much time to write a proper test for a unit check;
• Unit testing might only help with the anticipated or already found bugs/errors.

However, reading about the aforementioned risks you might notice, that they are about a developer’s professionalism level… If you work with a true highly-qualified developer, he might not encounter any risks of a kind.

Quality assurance, as one of the most important parts of software development, have a plenty of benefits from using unit testing on the very first stage. The bugs and errors become seen very soon, what allows to protect the project from failure. Unit testing simplifies the QA process a lot also because it deals only with the latest changes to the code, without rolling out all the ‘history’ of the project. Providing no-error results it significantly cuts the time necessary for the QA processing. Though recommended mainly to the big projects or companies, unit tests wouldn’t go amiss any size project that aims to be as impeccable as possible!

If you have your own experience in using unit testing for your project, we would greatly appreciate if you leave your comments with your evaluation of unit testing importance below!