Spring Boot Junit Example (2024)

In this tutorial, we'll demonstrate how to create a Spring Boot Junit example for simple GET rest api.

Create Spring Boot application

Create Spring Boot application from Spring Initializr.

Project Structure

Add Dependencies

Add below dependencies for Web - spring-boot-starter-web , for junit starter - spring-boot-starter-test and lombok - lombok for auto getters/setters in pom.xml.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.techgeeknext</groupId>
	<artifactId>SpringBootJunitExample</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>SpringBootJunitExample</name>
	<description>Spring Boot Junit Example</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.4.1.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>


		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>

	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>


</project>

Data Model

Create Employee class, contains id, name and role.

package com.techgeeknext.model;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class Employee {
	private long id;
	private String name;
	private String role;
}

Employee Controller to handle GET rest endpoint

package com.techgeeknext.controllers;

import com.techgeeknext.model.Employee;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EmployeeController {

    @GetMapping("/employee")
    public Employee getEmployee() {
        return Employee.builder().id(1).name("TechGeekNext").role("Admin").build();
    }
}

Spring Boot Junit Employee Test Class

1. Create EmployeeControllerTest class under the test/java folder which will call the GET rest endpoint and test the expected response values.
2. There are many ways for unit testing APIs. Spring Boot, JUnit, MockMvc, and Mockito are my preferred combination because they are all open-source and support Java, which is our primary language.
3. A Runner class is in charge of running JUnit tests, generally using reflection. @RunWith(EmployeeController. class) is an example of @RunWith, which defines a set of several test classes to run alongside the class where it is used.
4. MockMVC is a Spring MVC test framework class that assists in testing controllers by directly creating a Servlet container.
5. Create a MockMvc instance with the provided fully initialized WebApplicationContext.

package com.techgeeknext.test;

import com.techgeeknext.controllers.EmployeeController;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8_VALUE;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

@RunWith(SpringRunner.class)
@WebMvcTest(EmployeeController.class)
public class EmployeeControllerTest {

    @Autowired
    private WebApplicationContext applicationContext;

    @Autowired
    private MockMvc mockMvc;

    @Before
    public void setup() {
        mockMvc = MockMvcBuilders.webAppContextSetup(applicationContext).build();
    }

    @Test
    public void getEmployeeTest() throws Exception {
        mockMvc.perform(get("/employee"))
				.andExpect(status().isOk())
                .andExpect(content().contentType(APPLICATION_JSON_UTF8_VALUE))
				.andExpect(jsonPath("$.id").value("1"))
                .andExpect(jsonPath("$.name").value("TechGeekNext"))
				.andExpect(jsonPath("$.role").value("Admin"));
    }

}

Test Spring Boot Junit Example

1. Start the Spring Boot Application by running spring-boot:run or by running main class.

2. Test Junit Class

   Run the test case from the EmployeeControllerTest.java class by right-clicking and selecting "Run getEmployeeTest()" and we can see that the test case was successfully executed.

Download Source Code

The full source code for this article can be found below.

1. Download it here - Spring Boot Junit Example