Spring Boot MockMVC Example
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 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
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
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
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
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
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.
