The Spring Boot Starter Test dependency is a primary dependency for testing the Spring Boot Applications. It holds all the necessary elements required for the testing.
For the Unit testing controller layer REST APIs, we are going to use the following testing libraries:
- JUnit 5 Framework
- Mockito 4 (Latest)
- Hamcrest framework
- AssertJ Library
- JsonPath Library
It's the de facto standard testing framework for Java.
The current version of JUnit is 5+. The main goal of JUnit 5 is to support Java 8 and above, as well as enable many different styles of testing.
Learn JUnit at https://www.javaguides.net/p/junit-5.html
Mockito is a mocking framework. It is a Java-based library used to create simple and basic test APIs for performing unit testing of Java applications.
The main purpose of using the Mockito framework is to simplify the development of a test by mocking external dependencies and using them in the test code.
Learn about the Mockito framework at https://site.mockito.org/
Hamcrest is the well-known framework used for unit testing in the Java ecosystem. It's bundled in JUnit and simply put, it uses existing predicates – called matcher classes – for making assertions.
Hamcrest is commonly used with JUnit and other testing frameworks for making assertions. Specifically, instead of using JUnit’s numerous assert methods, we only use the API's single assertThat statement with appropriate matchers.
Learn more about Hamcrest at http://hamcrest.org/JavaHamcrest/tutorial
AssertJ is a Java library that provides a rich set of assertions and truly helpful error messages, improves test code readability, and is designed to be super easy to use within your favorite IDE.
Spring boot starter test dependency internally provides assertj-core dependency so we don’t have to add assertj-core dependency manually in our Spring boot project.
Read more about AssertJ at https://assertj.github.io/doc/
A Java DSL for reading JSON documents.
JsonPath expressions always refer to a JSON structure in the same way as XPath expressions are used in combination with an XML document. The "root member object" in JsonPath is always referred to as $ regardless of whether it is an object or array.
Read more about JsonPath at https://github.com/json-path/JsonPath
SpringBoot provides @WebMvcTest annotation to test Spring MVC Controllers. Also, @WebMvcTest based test run faster because it will load only the specified controller and its dependencies only without loading the entire application.
Spring Boot instantiates only the web layer rather than the whole application context. In an application with multiple controllers, you can even ask for only one to be instantiated by using, for example, @WebMvcTest(HomeController.class).
- Java 11+
- Spring Boot
- Lombok
- JUnit 5 Framework
- Hamcrest
- AssertJ
- JsonPath
- Mockito
- IntelliJ IDEA
- Docker
- Maven
- Clone this repository:
git clone https://github.com/hendisantika/spring-boot-unit-test-sample2.git - Navigate to the folder:
cd spring-boot-unit-test-sample2 - Run the test:
mvn clean test
