Spring Boot WebFlux test not finding MockMvc - spring

Question

Problem
I'm trying to run a simple spring boot test and I'm getting errors that suggest it can't MockMvc at runtime. Documentation suggests I'm using the correct annotations and I created my pom.xml using start.spring.io. Not sure why its having issues.
Error:
No qualifying bean of type 'org.springframework.test.web.servlet.MockMvc'
TestCode
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;
#RunWith(SpringRunner.class)
#SpringBootTest
#AutoConfigureMockMvc
public class MyWebApplicationTests {
#Autowired
MockMvc mockMvc;
#Test
public void Can_Do_Something() throws Exception {
mockMvc.perform(get("/hello-world")).andDo(print()).andExpect(status().isOk())
.andExpect(content().string(containsString("Hello World")));
}
}
Documentation:
I was using this doc as a reference ->
https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html#boot-features-testing-spring-boot-applications-testing-with-mock-environment
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.mywebapp</groupId>
<artifactId>webapp</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>my-webapp</name>
<description>Backend application</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.M1</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>10</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.0.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.el</groupId>
<artifactId>javax.el-api</artifactId>
<version>3.0.0</version>
</dependency>
<dependency>
<groupId>org.glassfish.web</groupId>
<artifactId>javax.el</artifactId>
<version>2.2.6</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</project>

Answer 1

As this Question seems to appear at the top of search lists when people are trying to test their endpoints after they've switched to Spring WebFlux, I'll add what I was able to determine here. (It should be noted that in the past I was having an incredibly hard time getting the WebTestClient to function with RestController annotated endpoints. But this code works. I think I was missing a dependency and it wasn't clear.)
MyService.java
#Service
public class MyService {
public String doSomething(String input) {
return input + " implementation";
}
}
MyController.java
#RestController
#RequestMapping(value = "/api/v1/my")
public class MyController {
#Autowired
private MyService myService;
#RequestMapping(value = "", method = RequestMethod.POST, consumes = {APPLICATION_JSON_VALUE})
public ResponseEntity<Mono<String>> processPost(#RequestBody String input)
{
String response = myService.doSomething(input);
return ResponseEntity.ok(Mono.just(response));
}
TestMyController.java
#ExtendWith(SpringExtension.class)
#WebFluxTest(MyController.class)
public class TestMyController {
#Autowired
private WebTestClient webTestClient;
#MockBean
private MyService myService;
#Test
public void testPost() throws Exception {
// Setup the Mock MyService. Note the 'mocked' vs 'implementation'
when(myService.doSomething(anyString())).thenAnswer((Answer<String>) invocation -> {
String input = invocation.getArgument(0);
return input + " mocked";
});
String response = webTestClient.post()
.uri("/api/v1/my")
.body(BodyInserters.fromObject("is"))
.accept(MediaType.APPLICATION_JSON)
.exchange()
.expectStatus().isOk()
.returnResult(String.class)
.getResponseBody()
.blockFirst();
assertThat(response).matches("is mocked");
}
}
The dependencies that can cause issues that are hard to diagnose appear to be from reactor-test. So if the WebTestClient is not working, make sure that dependency exists.
pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<version>2.1.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>2.1.5.RELEASE</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<version>3.2.9.RELEASE</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<artifactId>jackson-module-kotlin</artifactId>
<groupId>com.fasterxml.jackson.module</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter</artifactId>
<version>5.4.2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.google.truth</groupId>
<artifactId>truth</artifactId>
<version>0.45</version>
<scope>test</scope>
</dependency>

Answer 2

As pointed out by M. Deinum MockMvc isn't loaded for the WebFlux configuration in Spring Boot. You need to use WebTestClient instead. So replace AutoConfigureMockMvc with AutoConfigureWebTestClient and utilize the the webTestClient methods in its place.
One thing to note is that this is making actual web calls behind the scenes and will start the server. MockMVC does not start the server. What is the difference between MockMvc and WebTestClient?