Learn Java Unit Testing with Junit & Mockito in 30 Steps (Udemy.com)
Learn Mockito and JUnit - the most popular Java unit testing and mocking frameworks - with 25 Examples
Created by: in28Minutes Official
Last updated November 2024
Our take
Based on the ratings of 27,703 students, a sample of their written reviews and the syllabus, as the course stood in November 2024. No course pays to be reviewed.
This is a short, practical course on testing Java code with JUnit and Mockito, taught by Ranga Karanam of in28Minutes. It runs about 5 hours over 48 lectures, with 12 steps on JUnit, 18 on Mockito and a closing block on PowerMock for static methods, private methods and constructors. It assumes you can already write Java but have never tested it, and it walks through the Eclipse and Maven setup first. The course holds a 4.6 rating across 27,703 reviews.
Reviewers like the clear, step-by-step explanations. One says it gave a clear mindset on what mocking is and where it is useful, and a working developer says it refreshed what they knew and added a few new techniques. The criticism is steady, though. The course covers JUnit 4 only, and a September 2025 reviewer hit problems following the library-specific steps. Others call it too basic, mention mediocre audio, or say the instructor mostly reads code while scrolling instead of explaining how when() and then() work. There are no quizzes or coding exercises, and one student missed them.
Fair value for a five-hour primer, but expect to supplement it. It was last updated in November 2024 and still teaches the JUnit 4 style, so treat it as a way to learn what mocking is and why it matters, then check current docs for JUnit 5 and Mockito 5 syntax. For beginners to testing it is a sensible first stop. Experienced testers will find it basic.
Pros
- Starts from zero testing experience and builds from stubs to mocks to spies in small steps
- Explains why mocks exist before showing Mockito, which reviewers say made the idea click
- Covers PowerMock for static methods, private methods and constructors in a closing section
- Short enough to finish in a weekend: about 5 hours over 48 lectures
Cons
- Teaches JUnit 4 only, with no JUnit 5 or Mockito 5 coverage, per reviewers
- No quizzes or coding exercises, so practice is left entirely to the student
- Some low-star reviews call it basic, with mediocre audio and code read aloud rather than explained
This course helped me in gaining a clear mindset on what mocking is and how it actually works and where it is useful and related scenarios.
Suits Java programmers new to testing, not Java beginners. Eclipse and Maven are explained, but the syntax is assumed.
What you will learn
- You will Understand the Basics of Unit Testing with JUnit
- You will Learn the Most Popular Mocking Framework - Mockito
- You will Learn to Write Great Unit Tests using Mocking
- You will Learn to Use Mockito in combination with Junit and PowerMock
Course content
7 sections · 48 lectures · 5 hours of video 5 articles
- 1Introduction 2 free previews5 lectures · 7 min
- 2Unit Testing with JUnit 4 free previews15 lectures · 1.5 hours
- 3Getting Ready for Mockito 1 free preview2 lectures · 9 min
- 4Need For Mockito 1 free preview6 lectures · 46 min
- 5Mockito Basics6 lectures · 47 min
- 6Mockito Advanced7 lectures · 58 min
- 7Powermock with Mockito7 lectures · 44 min
Who it is for
The instructor says it suits
- Students who want to learn unit testing with Junit
- Students who want to learn mocking with Mockito
- We will help you install Eclipse and Maven
What you need before you start
- You have an attitude to learn while having fun :)
- You have Java Programming Experience and ZERO Experience with Junit and Mockito
- We will help you install Eclipse and get up and running with Maven
How it compares
Against the other 231 rated Udemy courses in Java on CourseDuck:
- Rating4.6 out of 5higher than 71% of them
- Reviews27,703#8 of 232 by number of reviews
- Length5 hoursshorter than 75% of them
- Last updatedNovember 2024more recently than 57% of them
Course Description
Writing Great Unit Tests distinguishes Good Programmers from Great Programmers.
In this course, you will learn how to Write Great Java Unit Tests with Mockito and JUnit.
WHAT OUR LEARNERS ARE SAYING:
5 STARS - When I’ve started this course I had very basic knowledge of JUnit and Mockito and now everything is clearer. It is a very good course for beginners. Everything was very well explained.
5 STARS - As always, Ranga offers an excellent way of teaching: coding from scratch, good explanation, useful examples for the real world job. He is not only an experienced programmer, but also a great teacher. I learned more than I expected. Thanks
5 STARS - It was my long time wish to learn Mockito and this instructor nailed it. Best 5hrs I spent ever. He is really good in what he is doing.
5 STARS - This course is a great tutorial to unit testing and standard practices of mocking. I would recommend it to even experienced developers who would be surprised to find some new ideas in here. Explanations are precise and detailed. Well done.
5 STARS - Very interesting course with good examples. Every topic was easy to understand because of author's awesome explanation. I rate this course as 5/5.
5 STARS - Very good course. The approach is very systematic and step by step. I really like the combination of theory and practical goes hand by hand. The journey from JUnit to Mockito to Powermock is very well described.
COURSE HIGHLIGHTS
You take 12 steps with JUnit and 18 steps with Mockito into unit testing proficiency.
Mocking with Mockito
Step 01 : Set up an Eclipse Project with JUnit and Mockito frameworks. First Green Bar.
Step 02 : Example to start understanding why we need mocks.
Step 03 : What is a stub? Create an unit test using Stub? Disadvantages of Stubs.
Step 04 : Your first Mockito code! Hurrah!!! Lets use Mockito to mock TodoService.
Step 05 : Stubbing variations with Mockito. A few mockito examples mocking List class : Multiple return values, Argument Matchers and throwing exceptions.
Step 06 : Introduction to BDD. Given When Then. BDD Mockito Syntax.
Step 07 : How to verify calls on a mock? Verify how many times a method is called. We will add deleteTodo method to the TodoService.
Step 08 : How to capture an argument which is passed to a mock?
Step 09 : Hamcrest Matchers.
Step 10 : Let's simplify things with Mockito Annotations. @Mock, @InjectMocks, @RunWith(MockitoJUnitRunner.class), @Captor
Step 11 : JUnit Rules. Using MockitoJUnit.rule() instead of @RunWith(MockitoJUnitRunner.class).
Step 12 : Real world Example with Spring
Step 13 : What is a spy? How to spy with Mockito?
Step 14 : Some Theory : Why does Mockito not allow stubbing final and private methods?
Step 15 : Using PowerMock and Mockito to mock a Static Method.
Step 16 : Using PowerMock and Mockito to invoke a private Method.
Step 17 : Using PowerMock and Mockito to mock a constructor.
Step 18 : Good Unit Tests.
JUnit Framework
Step 01 : Need for Unit Testing
Step 02 : Setting up your First JUnit
Step 03 : First Successful JUnit. Green Bar and assertEquals
Step 04 : Refactoring Your First JUnit Test
Step 05 : Second JUnit Example assertTrue and assertFalse
Step 06 : @Before @After
Step 07 : @BeforeClass @AfterClass
Step 08 : Comparing Arrays in JUnit Tests
Step 09 : Testing Exceptions in JUnit Tests
Step 10 : Testing Performance in JUnit Tests
Step 11 : Parameterized Tests
Step 12 : Organize JUnits into Suites
Start Learning Now. Hit the Enroll Button!
Instructor Details
- 4.6 Rating
27,703 Reviews
in28Minutes Official
Ranga Karanam, the founder of in28minutes, has 2 decades of experience with technology - architecture, design, and programming. We are helping learners take their first steps into modern cloud native technology and gain expertise on AWS, Azure, Google Cloud, Docker, Kubernetes amongst others.
Our happiest moments are when learners tag us on LinkedIn or reach out to us with their stories of getting their first job, getting a promotion, or a big raise.
----------------------
Ranga is multi-cloud certified - Google Cloud Certified Professional Cloud Architect, Google Cloud Certified Associate Cloud Engineer, AWS Certified Cloud Practitioner, Azure Fundamentals Certified AZ-900, DP-900 and AI-900.
Our courses are focused on Cloud Certifications (AWS, Azure, Google Cloud Platform - GCP), DevOps, Full Stack ( React, Angular ), Serverless, Programming, and Microservice Development with Java and Spring Boot.
Our Top Courses include:
1) Master Microservices with Spring Boot and Spring Cloud
2) Java Programming for Complete Beginners
3) Google Cloud Certification - Associate Cloud Engineer - 2021
4) DevOps For Beginners - Docker, Kubernetes, and Azure DevOps
5) Spring Framework Master Class - Java Spring the Modern Way
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Reviews
By Anonymized User on 5/3/2026
Mr Ranga made concepts very easy to learn, understand and implement in our project, flow of the course design is so simple easy to learn and remember the concepts. Thanks for making the course so easy and interesting to learn.
By Sukumar Sivasamy on 11/4/2025
The course provided a solid understanding of the key topics, and I was able to relate them to my daily development tasks. While I was already familiar with some parts, it still helped me refresh my knowledge and learn a few new techniques. Overall, it was a good match for me as a developer.
By Peter Ford on 9/27/2025
Fairly out of date, not well organised - content grouping vs videos, poor pace. Mediocre audio quality. Some visual overlays hide useful information. Yes it covers the basics and some theory. but this was very disappointing.
By Jonathan Josué Cáceres González on 5/29/2024
Me encanta el contenido y como explica, me hace entender fácilmente pese a la dificultad del idioma y el acento. Se nota que conoce lo que enseña y que le gusta enseñar.
By Nageswara Gupta on 2/11/2024
Very well structured course. It covered only JUnit4. There are some topics that can be covered from JUnit5 and also from Mockito 5.x This course is very old and need to be updated. But you can use it as starting point to get into Unit testing and Mocking.
By Rohit Rai on 1/7/2023
I tried learning Junit and Mockito using other online resources but was not able to gain the complete perspective and information of the same. This course helped me in gaining a clear mindset on what mocking is and how it actually works and where it is useful and related scenarios. Thanks a ton!!!! :)
By Leonid Korkulenko on 1/31/2021
Amazing course! It really does what it should - clearly explains what unit-tests are, how to write, and how to use advanced thing like mocking and stubbing. That's basically all what you need to start your road into the good designs of your programs. Thanks to In28Minutes! Awesome job! Keep rocking :)
By Mrityunjay Kumar on 12/20/2020
Good course
By Sagar Mane on 12/20/2020
nice video content and very nice explanation
By Yashas Samaga on 12/20/2020
JUnit, Mockito & Powermock basics with proper understanding delivered as promised.
looking forward to taking up more courses from the author.
By Shashank Kumar on 11/23/2020
na
By Raj Khare on 11/18/2020
very good course for starting the unit testing with Junit and Mockito. This course will make you comfortable in the unit testing starting from beginner level to expert. Teaching style and course materials are very good!!!...I can see the improvements in myself after spending times with course...thanks to In28Minutes!!!
Quality Score
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Overall Score : 92 / 100












