What is unit testing?

Hello, people! How is your life? I hope everything is good. Are you ready to know what I’m gonna tell you about not serious but a really important and valuable topic at the same time – “What is unit testing?”

In my opinion, you will like this topic because unit testing is one of the important technologies.

Therefore, many people want to start learning this material. This is not particularly new and has been used for many years. Elan Kay, American computer scientist said: “Technology is anything that wasn’t around when you were born”.

In this article, I want to give short information about unit testing and share my thoughts on that topic. If you are a newcomer in writing unit tests, I highly recommend you to read this topic. I hope after reading the article the number of those people who wanna provide unit testing will become more. For very resourceful beginners it will be very useful.

Now, let’s get started!

What does unit testing mean?

Have you ever heard about unit testing? I believe there are still some people who are not well acquainted with it. So, what is it?

Unit testing – is a level of software testing where individual components of the software are tested. This module is performed only by the developers. But for a better understanding, let us dive a little bit deeper and try to recollect what unit is.

A unit is the smallest testable part of any software. It usually has one or a few inputs and usually a single output. Then smaller the unit then better it is. It is always necessary to remember the conclusion of Edgverom Dextrom “Testing programs can prove the existence of errors, but will never prove their absence”. So, it becomes clear that unit testing is an important step in the development process.

How to provide unit testing? Let’s figure it out. Even if you think, you don’t use unit testing, you do. You collect your applications, press the button and check whether the result meets your expectations. You can rather often find molds with a bottom “Test”, or “TestController” and “MyServiceTestClient”. The unit tests are written in the same programming language as the source code of the application.

Now let’s move on to the next position. I know you’re anxious to get as much information as possible.

Types of unit testing

Unit Tests can be performed manually and automated.  The first test is performed by people pre-defined or defined for each test. Persons who use the manual method may have a document that describes the stage of the process.

The second test is performed by a special tool or independent program. Test data is entered or generated. The program establishes reports on failed test cases and also provides summaries of test cases.

It is important to add that why you should provide unit testing:

  • firstly, we can automate the code verification process;
  • secondly, think of the logic of the code.

It should be noted that unit testing helps you to:

  • identify the problem and correct it quickly;
  • be sure that the changes didn’t disturb the behavior of the method;
  • always know what to expect from a code.

Experience-based testing

Now, we move to another important point of unit testing. I totally recommend it to read every one. The coolest thing about experience-based testing.

The first thing to consider is what experience-based testing is?

Experience-based testing is when test methods and software testing techniques are fully based on experience. There are two most common forms of experience-based – testing – Ad-Hoc testing and exploratory testing.

Ad-Hoc testing

Of course Ad –Hoc – testing is a form of informal software testing. Ad- hoc testing is synonymous with random testing. The main advantage here is that Ad-Hoc testing often allows finding complex reproducible and subtle defects. Ad-Hoc testing is mostly performed when the owner does not operate on specific objectives.

Another definition of the exploratory testing

Exploratory testing is the simultaneous study of a software product the design of tests and their execution. According to James Bach research, testing is a method of designing tests in which the tester actively controls the design of the tests are performed and uses information obtained during the tests. If every next test we perform is based on the results of the preliminary test, it means that we use experimental testing.

What is the difference between Exploratory and Ad-Hoc testing?

The difference between Ad-Hoc and Exploratory Testing is that theoretically, Ad –Hoc testing can be done by anyone but, in turn, exploratory testing requires professional skills and mastery of certain testing techniques.

Advantages and disadvantages of unit testing

I suppose this is the main thing you are interested in. What peculiarities and pros does this testing have? Let’s cast some light on this point.

Advantages of unit testing include:

  • early problems detection which lessens the errors’ complexity;
  • problems’ solving costs;
  • changes to the code base can be done.

Disadvantages include:

  • tests do not usually reveal all errors and problems;
  • block of the tests’ sets;
  • testing of just one line requires writing more lines of test code.

It’s clear from these observations which advantages and disadvantages this unit testing may have. It’s recommended to use the unit testing in conjunction with other testing activities.

Unit testing techniques

An important aspect of the topic is unit testing techniques. Here is the shortlist of the main techniques you may use in your work:

  • Statement Coverage;
  • Decision Coverage;
  • Branch Coverage;
  • Condition Coverage;
  • Finite State Machine Coverage.

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Why is unit testing necessary?

In the final stage, I wanna tell you about why unit tests necessary in different ways. And now let’s read these points.  My own point of view is that unit tests provide a huge amount of help during the work over an application.

  • Faster development

When developers write single tests they spend less time, but later gain more confidence in changing the code.

  • Better design

When developers write tests, they focus on thinking about how to use their code across the system.

  • Pre-regression Tool

In case when developers perform tests they are allowed to do code reconstruction.

  • Reduced Cost

The error was very expensive if it was detected too late in the development stage. Single tests give the possibility to identify and correct at least the basic errors.


I hope you have received some new information about unit testing. Maybe this topic is a bit old but still necessary to discuss and light up. I tried to highlight the most important facts, which can be useful for you. There is also a myth that says, if testing is good, then more testing is better. Smart testing is good and will help to create a valuable and stable product.

In order to provide proper unit testing, you should keep in mind the advantages and disadvantages of the unit testing.


  • early problems detection which lessens the errors’ complexity;
  • problems’ solving costs;
  • changes to the code base can be done.


  • tests do not usually reveal all errors and problems;
  • block of the tests’ sets;
  • testing of just one line requires writing more lines of test code.

As for types of unit testing, I can enumerate:

  • manual;
  • automated;
  • exploratory;
  • experience-based testing;
  • Ad-Hoc testing.

When we get to the techniques of the unit testing, there are such types of them as:

  • Statement Coverage;
  • Decision Coverage;
  • Branch Coverage;
  • Condition Coverage;
  • Finite State Machine Coverage.

I reckon it is also important to notice that the unit testing reduces the costs of testing, makes the process of development faster as well as the better design. Furthermore, it functions as a pre-regression tool.

Thank you very much for reading! I hope, you have deepened your understanding of unit testing today! If you wanna read more, you may read this article which is also rather interesting: Good and great developers. What is the difference?

Thanks a lot and have a nice day!

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