Spring MockMvc tutorial

last modified October 18, 2023

Spring MockMvc tutorial shows how to test Spring MVC application with MockMvc.

Spring is a popular Java application framework for creating enterprise applications.

MockMvc

MockMvc is defined as a main entry point for server-side Spring MVC testing. Tests with MockMvc lie somewhere between between unit and integration tests.

Spring MockMvc example

The following application uses MockMvc to test a Spring MVC application. We create a test for a template and for a RESTful controller method.

pom.xml
src
├───main
│ ├───java
│ │ └───com
│ │ └───zetcode
│ │ ├───config
│ │ │ MyWebInitializer.java
│ │ │ WebConfig.java
│ │ └───controller
│ │ MyController.java
│ ├───resources
│ └───webapp
│ └───WEB-INF
│ └───templates
│ index.html
└───test
 └───java
 └───com
 └───zetcode
 └───controller
 MyControllerTest.java

This is the project structure.

<?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.zetcode</groupId>
 <artifactId>mockmvcex</artifactId>
 <version>1.0-SNAPSHOT</version>
 <packaging>war</packaging>
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 <maven.compiler.source>17</maven.compiler.source>
 <maven.compiler.target>17</maven.compiler.target>
 <spring-version>5.3.23</spring-version>
 </properties>
 <dependencies>
 <dependency>
 <groupId>ch.qos.logback</groupId>
 <artifactId>logback-classic</artifactId>
 <version>1.4.0</version>
 </dependency>
 <dependency>
 <groupId>javax.servlet</groupId>
 <artifactId>javax.servlet-api</artifactId>
 <version>4.0.1</version>
 <scope>provided</scope>
 </dependency>
 <dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>4.12</version>
 <scope>test</scope>
 </dependency>
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-webmvc</artifactId>
 <version>${spring-version}</version>
 </dependency>
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-test</artifactId>
 <version>${spring-version}</version>
 </dependency>
 <dependency>
 <groupId>org.thymeleaf</groupId>
 <artifactId>thymeleaf-spring5</artifactId>
 <version>3.0.11.RELEASE</version>
 </dependency>
 <dependency>
 <groupId>org.thymeleaf</groupId>
 <artifactId>thymeleaf</artifactId>
 <version>3.0.11.RELEASE</version>
 </dependency>
 </dependencies>
 <build>
 <plugins>
 <plugin>
 <groupId>org.apache.maven.plugins</groupId>
 <artifactId>maven-war-plugin</artifactId>
 <version>3.3.2</version>
 </plugin>
 </plugins>
 </build>
</project>

In the pom.xml file we have the following dependencies: logback-classic, javax.servlet-api, junit, spring-webmvc, spring-test, thymeleaf-spring5 and thymeleaf.

package com.zetcode.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
@Configuration
public class MyWebInitializer extends
 AbstractAnnotationConfigDispatcherServletInitializer {
 @Override
 protected Class<?>[] getRootConfigClasses() {
 return null;
 }
 @Override
 protected Class<?>[] getServletConfigClasses() {
 
 return new Class[]{WebConfig.class};
 }
 @Override
 protected String[] getServletMappings() {
 
 return new String[]{"/"};
 }
}

MyWebInitializer registers the Spring DispatcherServlet, which is a front controller for a Spring web application.

@Override
protected Class<?>[] getServletConfigClasses() {
 
 return new Class[]{WebConfig.class};
}

The getServletConfigClasses returns a web configuration class.

package com.zetcode.config;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry;
import org.thymeleaf.spring5.SpringTemplateEngine;
import org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver;
import org.thymeleaf.spring5.view.ThymeleafViewResolver;
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"com.zetcode"})
public class WebConfig {
 @Autowired
 private ApplicationContext applicationContext;
 @Bean
 public SpringResourceTemplateResolver templateResolver() {
 var templateResolver = new SpringResourceTemplateResolver();
 templateResolver.setApplicationContext(applicationContext);
 templateResolver.setPrefix("/WEB-INF/templates/");
 templateResolver.setSuffix(".html");
 return templateResolver;
 }
 @Bean
 public SpringTemplateEngine templateEngine() {
 var templateEngine = new SpringTemplateEngine();
 templateEngine.setTemplateResolver(templateResolver());
 templateEngine.setEnableSpringELCompiler(true);
 return templateEngine;
 }
 @Bean
 public ViewResolver viewResolver() {
 var resolver = new ThymeleafViewResolver();
 var registry = new ViewResolverRegistry(null, applicationContext);
 resolver.setTemplateEngine(templateEngine());
 registry.viewResolver(resolver);
 return resolver;
 }
}

The WebConfig enables Spring MVC annotations with @EnableWebMvc and configures component scanning for the com.zetcode package. It sets up the Thymeleaf engine.

package com.zetcode.controller;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import java.time.LocalDateTime;
@Controller
public class MyController {
 @GetMapping(value = "/", produces = MediaType.TEXT_HTML_VALUE)
 public String home(Model model) {
 model.addAttribute("now", LocalDateTime.now());
 return "index";
 }
 @GetMapping(value = "/message", produces = MediaType.TEXT_PLAIN_VALUE)
 @ResponseBody
 public String message() {
 return "Hello there!";
 }
}

MyController provides two handler methods. The home method return a view with a single attribute and the message method returns a plain text message. In our tests we test these two methods.

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
 <meta charset="UTF-8">
 <title>Home page</title>
</head>
<body>
<p>
Today is: <span th:text="${now}"></span>
</p>
</body>
</html>

This is the index.html view.

package com.zetcode.controller;
import org.junit.Before;
import org.junit.Test;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.view;
public class MyControllerTest {
 private MockMvc mockMvc;
 @Before
 public void setup() {
 this.mockMvc = MockMvcBuilders.standaloneSetup(new MyController()).build();
 }
 @Test
 public void testHomePage() throws Exception {
 this.mockMvc.perform(get("/"))
 .andExpect(status().isOk())
 .andExpect(view().name("index"))
 .andDo(MockMvcResultHandlers.print())
 .andReturn();
 }
 @Test
 public void testMessagePage() throws Exception {
 this.mockMvc.perform(get("/message")).andExpect(status().isOk())
 .andExpect(content().string("Hello there!"));
 }
}

MyControllerTest tests the two handlers.

private MockMvc mockMvc;
@Before
public void setup() {
 this.mockMvc = MockMvcBuilders.standaloneSetup(new MyController()).build();
}

We set up the MockMvc. We add the MyController to the standalone setup. The MockMvcBuilders.standaloneSetup allows to register one or more controllers without the need to use the full WebApplicationContext.

@Test
public void testHomePage() throws Exception {
 this.mockMvc.perform(get("/"))
 .andExpect(status().isOk())
 .andExpect(view().name("index"))
 .andDo(MockMvcResultHandlers.print());
}

We test the home page. We verify the status and the returned view name. We also print the result.

@Test
public void testMessagePage() throws Exception {
 this.mockMvc.perform(get("/message")).andExpect(status().isOk())
 .andExpect(content().string("Hello there!"));
}

We test the message page. Since it is a RESTful method, we verify the status and the returned string.

$ mvn -q test

We run the tests with mvn -q test.

In this article we have created tests for Spring MVC with MockMvc.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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