Top 5 Courses to Learn JUnit and Test Driven Development in Java - Best of Lot

Hello guys, today, we'll talk about JUnit and Unit testing, one of the critical skills for any Software developer. You may already know that JUnit and Mockito are two of the most popular testing libraries for Java applications, and you will find them in almost every Java application classpath. I often meet and work with Java developers who know Java well but haven't written a single unit test. When I ask them why don't you write unit tests, they come up with many excuses like they don't have time for writing unit tests, there is always deadline pressure, and some of the honest guys will tell you that they tried writing but give-up after 10-15 minutes due to difficulty in testing their code.

Whatever your reason for not writing a unit test, I don't think it's going to work anymore because in today's world of DevOps and Automation, there is increased focus on code-reviews, unit testing, and integration testing and you just can't get away by not writing tests.

In fact, every good software developer must know how to write unit tests and nearly all Java jobs ask for unit testing skills, and those who don't mention about it, assume that you already know unit testing.

Unit tests are at the lowest level and typically checks a single method to confirm that they return the correct result. Example toCelcius()).

Don't worry if you haven't written any unit test, as long as you can accept the fact and willing to learn unit testing in Java using JUnit and Mockito, you are in good shape.

In the past, I have shared some great books to learn unit testing in Java and today, I am going to share some of the online courses you can use to learn JUnit 5 or Jupiter, the latest version of JUnit library, and Mockito to write a unit test for your Java application.

You can use these online courses to get up-to-speed with JUnit and Mockito. This will not only help you in your current job and project but also increases your chances of getting a job with better pay, believe me, everyone loves good software developer, and there is always a demand for a programmer who can code and write good tests.

What are Unit testing and Why Write Unit tests

If you are thinking, why should I write unit tests? Shouldn't I get paid for writing code to add functionality? Then let me tell you that Unit tests are necessary for every good software, and every programmer should write a Unit test.

It increases confidence during development and helps you to write cleaner, more reusable code, and also helps you to catch bugs earlier. Catching mistakes in the development phase is a lot less costly than finding them in production. It not only will save you from embarrassment but also your company and user from frustration.

Talking about Unit testing, Unit tests are typically written by Software developer when they develop new features and not by software testers.

Now that if you are convinced and want to learn unit testing in Java, then you can explore these online courses to learn unit testing in Java.

Top 5 Online Courses to learn JUnit in depth

In the Java world, JUnit is the defacto standard for unit testing, ut you often need Mockito, a mocking framework which is often used along with JUnit to make unit testing earlier.

I have been using JUnit since JUnit 3 was there, which was prior to annotations. Then JUnit 4 comes in 2006, and after 11 years of a long wait, JUnit 5 came in September 2017.

As of writing, this is the latest version of JUnit, and every Java developer should learn it. Even though you still find a lot of projects still using JUnit 4, learning JUnit 5 will help you to write a better test and faster by leveraging new features.

Most of these course covers JUnit 5, but I have also included a course on test-driven development to learn some best practices and techniques for writing better unit tests.

1. Java Unit Tests for Beginners

This is one of the best courses to learn how to write Java unit tests with JUnit 5 or Jupiter. This course is ideal for all kind of Java developers, I mean from intermediate Java developer with years of experience to beginners who have not written a single unit test before.

The course is full of practical examples, additional exercises, a unit testing cheat sheet. It starts from scratch telling you about what is a unit test and why you should do it before teaching you how to do it step by step.

The course also teaches you unit testing best practices and their sample project, The HealthyCoder example makes things really interesting. The course is filled with exercises and an extra JUnit cheat sheet and provides enough knowledge to a Java developer to start writing unit tests on your own.

On top of all of this, instructor Adrian Więch has an excellent voice, just perfect for teaching, and his voice modulation, pace, and skill to make things simpler make this course very interesting. I strongly recommend this course to all Java developer who wants to learn Unit testing this year.

2. Learn Unit Testing with JUnit & Mockito in 30 Steps

This is another awesome course to learn Mockito and JUnit - the most popular unit testing and mocking frameworks in Java worlds - with 25 Examples.

I am a big fan of Ranga and his in28Minutes courses as they focus on 20% of important stuff, which is used 80% of the time. Having seen his Spring Masterclass and Microservice course, I know that this will also be the good one, and it didn't disappoint me.

The course takes a step by step approach and in 30 steps will teach you enough Mockito and JUnit so that you can write your own tests. The first 18 steps are about Mockito, and the last 12 are of JUnit.

The course not only covers basic stuff like writing simple tests but also covers more advanced concepts like testing static methods, Organize JUnit tests into Suites, Parameterized Tests, Testing Exceptions in JUnit Tests and in general how to write better tests.

Overall, a good, hands-on, and short course to learn Mockito and JUnit in less than 4.5 hours.

3. Java Unit Testing with JUnit 5

I recently come across this new online platform for learning called Educative. It's a bit different than Udemy and Pluralsight because it's interactive and allows you to run code right from the web page, which makes it very effective.

Like the previous two courses, this course will also teach you how to write unit tests with JUnit 5, but it also covers topics like why unit tests are important and structure of good unit tests, assertions, assumptions, and parameterized tests and more.

If you like interactive learning, then you can check out this course; it comes with 3 Free previous lessons and the 30-day return policy, which is good enough to give it a go.

4. Practical Test-Driven Development for Java Programmers

Learning JUnit is one thing, and writing unit tests is another. It's easy to write a trivial unit test for the sample project, but when you go into a real project where TDD has not been used, and no unit test is writing, you will find a lot of challenges to write your very first test, this course helps there.

I have purposefully included this course because I believe learning TDD and Unit testing, in general, is as important as learning JUnit and Mockito.

The instructor Matt Greencroft is very experienced and will teach you how to write unit tests for trickier scenarios and show you TDD techniques to fix applications that weren't developed using TDD.

My favorite part of this course is Chapter 10, handling legacy code, as this is a Java developer needs to do in his day-to-day coding. I have learned a lot of good stuff from this course and feel I know unit testing better than before. Hence I highly recommend this course to all Java developer who wants to learn unit testing or improve this their TDD skills.

5. Test-Driven Development Practices in Java

This is another course I have included on Test-Driven Development (TDD) practices and tools supporting TDD on the Java Platform, including JUnit and Mockito.

It nicely complements the previous course and covers things that are not covered theirs like PowerMock and DBUnit.

Instructor Mike is a solution architect for US Foods and worked in technology for over 15 years, holding roles focused on technical leadership, solution architecture, and enterprise architecture, which means you will learn a lot from his experience.

Though, you would need a Pluralsight membership to access this course, which costs around $29 per month or $299 per year. It may seem costly, but to be honest with you, it's completely worth as it gives you access to 5000+ online courses on Pluralsight and numerous quizzes and exercises to learn any technology you want.

I was lucky to get the membership in just $199 in one of their sales, and I can tell you its complete worth of it. Anyway, even if you don't have a membership, you can still get access to this course by using their 10-day FREE Pass, which allows 200 minutes of access, enough to complete this course.

That's all about some of the best courses to learn Mokcitor and JUnit. I have to tell my readers to learn unit testing for a long time. I had included this as the first thing in my list of 10 things Java Programmer should learn and also shared some free courses to learn JUnit earlier. If you don't have any goal, make unit testing your top priority for this year.

Worth noting is that JUnit 5 tests will run with Java 8 or above, so it's also good to learn Java 8 if you haven't. Always remember, Writing better Unit Tests distinguishes Good Programmers from average Programmers.

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Thanks a lot for reading this article so far. If you like these JUnit 5 online courses, then please share it with your friends and colleagues. If you have any questions or feedback or you want another course to add in this list, feel free to drop a note. All the best with your Unit testing journey.

P. S. - If you are looking for some free JUnit courses to start with, then you can also take a look at this list of free courses to learn JUnit for unit testing in Java.

P. S. S. -If you like books more than courses, then you can also check out this list of JUnit books for Java developers.