Testing Spring Boot App with JUnit, Mockito & Testcontainers

Ramesh Fadatare (Java Guides)

In this course, you will learn how to write Unit tests and Integration tests in BDD style for Spring Boot applications as well as Spring WebFlux applications using JUnit 5, Mockito, AssertJ, Hamcrest, JsonPath, and Testcontainers frameworks.

Important note: This course updated to use Spring Boot 3.

Type the code along with me in the videos. If you follow along with me then this will enhance your learning experience.

The source code and PDF files (class notes) are available for download.

Spring Boot Overview

Spring Boot is an opinionated framework that helps developers build Spring-based applications quickly and easily.

The main goal of Spring Boot is to quickly create Spring-based applications without requiring developers to write the same boilerplate configuration again and again.

Spring Boot is a very popular framework to develop REST web services and microservices.

Spring WebFlux Overview

Spring 5 includes Spring WebFlux, which provides reactive programming support for web applications.

Spring WebFlux internally uses Project Reactor and its publisher implementations, Flux and Mono.

The new framework supports two programming models:

Annotation-based reactive components
Functional routing and handling

In this course, we will focus on building reactive REST APIs using annotation-based reactive components.

What you'll learn?

Learn to write industry-standard Unit and Integration tests in BDD (Behaviour Driven Development) style using Spring Boot Starter Test dependency from scratch
Learn how to use BDD (Behaviour Driven Development) format that is given/when/then to write Unit tests.
Learn to Unit test the Spring boot application Repository layer
Learn to Unit test the Spring boot application Service layer
Learn to Unit test the Spring boot application Controller layer
Learn how to do Integration testing for the Spring boot application.
Learn how to do Integration testing using Testcontainers // very important
You will learn to use the most important Unit Testing
You will learn to write Unit tests using Mocks and Stubs created with Mockito
Learn how to use Mockito annotations to create mock objects.
Learn to Write Integration Tests using a MySQL database.
You will learn to Write
Learn Building Reactive"
"Ramesh explains things very well. His instructions are easy to follow and understand. The course is very beneficial"
" Well structured course covering all layers of testing
Implement each method with the "right to the point" explanation
Nice introduction to TestContainers
Easy to code along
Fast answers from the instructor
Looking for more deep dives courses such as Maven, Gradle, DevOps tools used in production"
"Awesome course.
All the basics needed to test a spring application are discussed, and more.
Exactly what i needed and coudn't find anywhere.
Ramesh is a great instructor.
Thank you sir . "
"A very good course explained with excellent examples.
Lot to learn from this course, covered every layer of a typical Spring Boot application."
"I really appreciate the trainer Ramesh to providing is this amazing course,
the content of this course and explanation is great."
"Wonderful Sir, Loved the way u explain things. And I am very lucky that I found this course at right time."
"I am personally very impressed with this course, if you dont have any prior experience of unit testing I am pretty sure that after taking this course you will feel more confident and I would be happy if the lecturer could also release some training tutorials about Microservices and TDD approach. thanks and wish you all the successes."
"Even though as a experience guy, this course was very useful.."
"The course is great and covers all I need to create my tests.
I truly recommend it ."
"Great course. This is the second course I am taking from Ramesh. Interesting so far."
"Awesome course and highly recommend it."
"This course is a good match for me. Especially so because it's new and up to date."
"great teacher and great course"
"Yes this is a good match for me and I am glad I enrolled for this. I personally prefer teaching of ramesh.fadatare. I started to watch his videos from YouTube and also gone through his comments to few problems in stack overflow. I thought it would be good if I can go through all his videos in one go."
"this is what they ask you to do on a real job... please do more courses ramesh.. amazing as always"

Enroll now

Or start a personal plan

And upskill your team with Udemy

What's inside

Learning objectives

Learn to write industry-standard unit and integration tests in bdd (behaviour driven development) style using spring boot starter test dependency from scratch
Learn how to use bdd (behaviour driven development) format that is given/when/then to write unit tests.
Learn to unit test spring boot application repository layer
Learn to unit test spring boot application service layer
Learn to unit test spring boot application controller layer - unit test rest api's
Learn how to do integration testing for the spring boot application
You will learn to use the most important unit testing annotations - @springboottest, @webmvctest, @datajpatest, and @mockbean
Use all the frameworks in spring boot starter test - junit, spring test, spring boot test, assertj, hamcrest, mockito, jsonassert, and jsonpath.
You will learn to write unit tests using mocks and stubs created with mockito

Learn how to use mockito annotations to create mock objects.
Learn to write integration tests using a mysql database
You will learn to write independent integration tests for restful web services talking with multiple layers - controller, service, and repository layers.
Learn to write integration tests using a testcontainers
Learn building reactive crud rest apis using spring webflux and mongodb
Learn unit testing reactive crud rest apis using junit and mockito
Learn integration testing reactive crud rest apis using webtestclient
Show more
Show less

Learn to write industry-standard unit and integration tests in bdd (behaviour driven development) style using spring boot starter test dependency from scratch
Learn how to use bdd (behaviour driven development) format that is given/when/then to write unit tests.
Learn to unit test spring boot application repository layer
Learn to unit test spring boot application service layer
Learn to unit test spring boot application controller layer - unit test rest api's
Learn how to do integration testing for the spring boot application
You will learn to use the most important unit testing annotations - @springboottest, @webmvctest, @datajpatest, and @mockbean
Use all the frameworks in spring boot starter test - junit, spring test, spring boot test, assertj, hamcrest, mockito, jsonassert, and jsonpath.
You will learn to write unit tests using mocks and stubs created with mockito
Learn how to use mockito annotations to create mock objects.
Learn to write integration tests using a mysql database
You will learn to write independent integration tests for restful web services talking with multiple layers - controller, service, and repository layers.
Learn to write integration tests using a testcontainers
Learn building reactive crud rest apis using spring webflux and mongodb
Learn unit testing reactive crud rest apis using junit and mockito
Learn integration testing reactive crud rest apis using webtestclient
Show more
Show less

Syllabus

Introduction

Course overview and roadmap

Best Way to Take This Course and How to Get Help

What is Unit testing and Integration testing?

Best practices for Unit testing in Java

Download Source Code

Download All the Important Lecture Notes in PDF

JUnit 5 and Mockito Annotations Cheat Sheets

This Course Migrated to Spring Boot 3

Spring Boot Project Setup

Create and Set up Spring Boot Project in IntelliJ IDEA

Understanding Spring boot starter test dependency

Create JPA Entity

Create Spring Data JPA repository

End of this section of lectures, students should able to write Unit tests for Spring Data JPA repository layer components.

Repository layer Unit testing overview

Spring Boot @DataJpaTest annotation

Unit test for save employee operation

Unit test for get all employees operation

Unit test for get employee by id operation

Unit test for get employee by email operation (Spring Data JPA query method)

Unit test for update employee operation

Unit test for delete employee operation

Unit test Spring Data JPA custom query method using JPQL with index parameters

Unit test Spring Data JPA custom query method using JPQL with named parameters

Unit test Spring Data JPA custom native query with index parameters

Unit test Spring Data JPA custom Native query with Named parameters

Refactoring JUnit tests to use @BeforeEach annotation

Download source code of this section

Unit test deleteEmployee REST API

End of this section of lectures, students should able to write Unit tests for Service layer components.

Service Layer unit testing overview

Create EmployeeService with saveEmployee method

Quick Recap of Mockito basics (before writing JUnit tests to use Mock objects)

Unit test for EmployeeService saveEmployee method

Using @Mock and @InjectMocks annotations to mock the object

Unit test for saveEmployee method which throws Exception

Unit test for EmployeeService getAllEmployees method - Positive Scenario

Unit test for EmployeeService getAllEmployees method - Negative Scenario

Unit test for EmployeeService getEmployeeById method

Unit test for EmployeeService updateEmployee method

Unit test for EmployeeService deleteEmployee method

End of this section of lectures, students should able to write Unit tests for controller layer components (Unit test REST APIs).

Controller Layer unit testing overview

Overview of @WebMvcTest annotation

@WebMvcTest VS @SpringBootTest

Build createEmployee REST API

Unit test createEmployee REST API

Build GetAllEmployees REST API

Unit test GetAllEmployees REST API

Refactoring JUnit test to use static imports

Build getEmployeeById REST API

Unit test getEmployeeById REST API - Positive Scenario

Unit test getEmployeeById REST API - Negative Scenario

Build updateEmployee REST API

Unit test updateEmployee REST API - Positive Scenario

Unit test updateEmployee REST API - Negative Scenario

Build deleteEmployee REST API

Solution for All the Assignments in One Video

End of this section of lectures, students should able to write Integration tests for Spring boot application using MySQL database

Integration testing overview

@SpringBootTest annotation overview

Configure MySQL database for integration testing

Create a base for Integration testing

Integration test for create employee REST API

Integration test for get all employees REST API

Integration test for get employee by id REST API - Positive & Negative Scenarios

Integration test for update employee REST API - Positive & Negative Scenarios

Integration test for delete employee REST API

Integration testing EmployeeRepository using MySQL database

End of this section of lectures, students should able to write Integration tests for Spring boot application using Testcontainers

What problem does Testcontainers solve

Testcontainers overview

Adding Testcontainers

Integration Testing EmployeeController using Testcontainers

Using @DynamicPropertySource

Singleton containers pattern

Integration Testing EmployeeRepository using Testcontainers

You can download the source code of this section as a zip file (attached to this lecture)

Assignments and Solutions

Assignments for You

Quiz - Test Yourself

Quiz to Test Knowledge About This Course

Spring WebFlux - Build Reactive CRUD REST APIs

Spring WebFlux Overview

Spring Boot WebFlux Application Architecture

Deploy MongoDB in Docker Container

Create and Set up Spring Boot Project in IntelliJ IDE

Create Employee Entity

Create EmployeeRepository and Understanding Internals

Create EmployeeDto and EmployeeMapper

Build Reactive Add Employee REST API

Build Reactive Get Employee REST API

Build Reactive Get All Employees REST API

Build Reactive Update Employee REST API

Build Reactive Delete Employee REST API

Good to know

Know what's good

, what to watch for

, and possible dealbreakers

Demystifies Spring Boot and Spring WebFlux with emphasis on Reactive programming

Provides complete hands-on practice with Junit 5, Mockito, AssertJ, Hamcrest, JsonPath, and Testcontainers frameworks

Covers all layers of full stack testing with an emphasis on unit testing

Introduces Spring Boot Starter Test dependency for BDD style tests

Teaches industry-standard unit and integration testing practices

Employs a practical approach with clear step-by-step instructions

Save this course

Save Testing Spring Boot App with JUnit, Mockito & Testcontainers to your list so you can find it easily later:

Save

Activities

Be better prepared before your course. Deepen your understanding during and after it. Supplement your coursework and achieve mastery of the topics covered in Testing Spring Boot App with JUnit, Mockito & Testcontainers with these activities:

Review key Java fundamentals

Show steps

Reinforces core concepts of Java by revisiting key concepts before starting the course.

Browse courses on Java Basics

Show steps

Review the Java SE Tutorial
Complete Java SE Tutorial exercises
Solve Java coding problems (e.g., LeetCode)

Follow online tutorials on JUnit 5 and Mockito

Show steps

Provides hands-on practice with the testing frameworks used in the course.

Show steps

Find tutorials on JUnit 5 and Mockito
Follow the tutorials and complete the exercises

Write unit tests for Spring Boot application components

Show steps

Strengthens understanding of unit testing and its implementation in Spring Boot applications.

Show steps

Create a simple Spring Boot application
Write unit tests for the application components (e.g., repository, service, controller)
Run the unit tests and debug any failures

Show all three activities

Career center

Learners who complete Testing Spring Boot App with JUnit, Mockito & Testcontainers will develop knowledge and skills that may be useful to these careers: