Spring Boot MockMVC Example

Last Updated : 06 Jan, 2025

Automated testing plays a vital role in the software industry. In this article, let us see how to do the testing using MockMvc for a Spring Boot project. To test the web layer, we need MockMvc and by using @AutoConfigureMockMvc, we can write tests that will get injected. SpringBootApplication is an excellent one that adds the following

@Configuration
@EnableAutoConfiguration
@EnableWebMvc
@ComponentScan

The application can ordinarily run as a Java application and hence development wise it is easier. Let's see the concept via a sample project

Example Project

Project Structure:

As it is a maven project, all dependencies are available under

pom.xml

Dependencies like

JDK 1.8
Spring version from 2.2.5 onwards
Maven 3.2+ and in the case of Gradle, it is Gradle 4+

We should add all the dependencies in pom.xml(in the case of the Maven project)

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.gfg.sample</groupId>     <artifactId>sampleboot-unit-testing-with-mock-mvc</artifactId>     <version>1.0-SNAPSHOT</version>      <parent>         <groupId>org.springframework.boot</groupId>         <artifactId>spring-boot-starter-parent</artifactId>         <!-- Mandatory -->         <version>2.2.5.RELEASE</version>     </parent>      <properties>         <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>         </dependency>     </dependencies> </project>

We are using MockMvc to test the web layer. That is we should have a model. a controller, and a view. Let us see the controller file

WelcomeMvcController.java

Each and every method should have either Getmapping or Postmapping

Java

import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.GetMapping;  @Controller public class WelcomeMvcController {     @Autowired     private WelcomeService welcomeService;          @GetMapping(value = "/")     public String greeting1(String name, Model model) {         model.addAttribute("welcome", welcomeService.greetingMessage1(name));         return "welcome-page";     }          @GetMapping(value = "/event")     public String greeting2(String name, Model model) {         model.addAttribute("welcomeToEvent", welcomeService.greetingMessage2(name));         return "event-page";     } }

Required services are written in the service file

WelcomeService.java

Java

import org.springframework.stereotype.Service;  @Service public class WelcomeService {     public String greetingMessage1(String name) {         return String.format("Welcome , %s to the world of programming!!!", name );     }        public String greetingMessage2(String attendee) {         return String.format("Welldone , %s You are selected to the contest!!!", attendee );     } }

SpringBoot Application is run as an ordinary Java application only

WebAppMain.java

Java

import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication;  @SpringBootApplication public class WebAppMain {     public static void main(String[] args) {         SpringApplication.run(WebAppMain.class, args);     } }

Now let us start to write the test class that tests the web layer by using MockMvc

WelcomeWebAppTest.java

Java

import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.context.junit4.SpringRunner; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.request.MockMvcRequestBuilders; import org.springframework.test.web.servlet.result.MockMvcResultHandlers; import org.springframework.test.web.servlet.result.MockMvcResultMatchers;  @RunWith(SpringRunner.class) @SpringBootTest @AutoConfigureMockMvc public class WelcomeWebAppTest {     @Autowired     private MockMvc mockMvc;      @Test     // We have to write out expectations and the        // expectations need to match with actuals       // When this is run, it imitates and accesses        // the web layer and get the output.     public void testWelcome() throws Exception {         this.mockMvc.perform(MockMvcRequestBuilders.get("/").param("name", "Geeks"))                 .andExpect(MockMvcResultMatchers.status().isOk())                 .andExpect(MockMvcResultMatchers.model().attribute("welcome",                         "Welcome , Geeks to the world of programming!!!"))                 .andExpect(MockMvcResultMatchers.view().name("welcome-page"))                 .andDo(MockMvcResultHandlers.print());     }      @Test     public void testWelcomeToEvent() throws Exception {         this.mockMvc.perform(MockMvcRequestBuilders.get("/event").param("name", "Geeks"))                 .andExpect(MockMvcResultMatchers.status().isOk())                 .andExpect(MockMvcResultMatchers.model().attribute("welcomeToEvent",                         "Welldone , Geeks You are selected to the contest!!!"))                 .andExpect(MockMvcResultMatchers.view().name("event-page"))                 .andDo(MockMvcResultHandlers.print());     }  }

Once the project is complete and does not contain any errors, we can run the test file as an ordinary JUNIT application

Console Output:

Once we are getting response 200 means the service is available and the parameters are passed properly and it is producing a positive response. With that response, we are comparing the details by means of

Java

this.mockMvc.perform(MockMvcRequestBuilders.get("/").param("name", "Geeks"))                 .andExpect(MockMvcResultMatchers.status().isOk()) // checking status                 .andExpect(MockMvcResultMatchers.model().attribute("welcome",                         "Welcome , Geeks to the world of programming!!!")) // sent attribute and its value check                 .andExpect(MockMvcResultMatchers.view().name("welcome-page")) // its view name check                 .andDo(MockMvcResultHandlers.print());

Like this, we can test the web layer in the above-said ways

Conclusion

Automated testing helps to avoid tons of errors and error-free code and helps for good quality software. In the Spring Boot project, we can use MockMvc and can achieve the same.

Spring Boot MockMVC Example

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