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SpringRunner tutorial

SpringRunner tutorial shows how to test Spring applications with SpringRunner.

Spring is a popular Java application framework. In the tutorial, we use Spring 5 version.

SpringRunner

SpringRunner is an alias for the SpringJUnit4ClassRunner, which joins JUnit testing library with the Spring TestContext Framework. We use it with @RunWith(SpringRunner.class).

With SpringRunner, we can implement standard JUnit 4-based unit and integration tests.

The Spring TestContext Framework provides generic, annotation-driven unit and integration testing support that is agnostic of the testing framework in use (JUnit, TestNG).

SpringRunner example

In the following application we test a simple service with SprigRunner. The application is a Spring standalone console application.

The application contains two property files: one file is for the production application, the other one for testing.

pom.xml
src
├───main
│   ├───java
│   │   └───com
│   │       └───zetcode
│   │           │   Application.java
│   │           ├───config
│   │           │       AppConfig.java
│   │           └───service
│   │                   HelloService.java
│   └───resources
│           application.properties
│           logback.xml
└───test
    ├───java
    │   └───com
    │       └───zetcode
    │           └───service
    │                   HelloServiceTest.java
    └───resources
            appTest.properties

This is the project structure.

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.zetcode</groupId>
    <artifactId>springrunnerex</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <spring-version>5.1.3.RELEASE</spring-version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring-version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring-version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring-version}</version>
        </dependency>

        <dependency>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-all</artifactId>
            <version>1.3</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.6.0</version>
                <configuration>
                    <mainClass>com.zetcode.Application</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

This is the Maven build file. We have the following dependencies: logback-classic for logging, spring-context and spring-core are basic Spring dependencies, spring-test is for testing, hamcrest-all contains all modules for the Hamcrest matching library, and JUnit is the library for unit testing.

The exec-maven-plugin helps execute system and Java programs.

resources/logback.xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <logger name="org.springframework" level="ERROR"/>
    <logger name="com.zetcode" level="INFO"/>

    <appender name="consoleAppender" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <Pattern>%d{HH:mm:ss.SSS} %blue(%-5level) %magenta(%logger{36}) - %msg %n
            </Pattern>
        </encoder>
    </appender>

    <root>
        <level value="INFO" />
        <appender-ref ref="consoleAppender" />
    </root>
</configuration>

The logback.xml is a configuration file for the Logback logging library.

resources/application.properties
app.message=Hello there!

The application.properties contains one message property, which is displayed by the HelloMessage service.

com/zetcode/AppConfig.java
package com.zetcode.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

@Configuration
@ComponentScan(basePackages = "com.zetcode")
@PropertySource("application.properties")
public class AppConfig {
}

AppConfig configures component scanning and loads properties from the provided file.

com/zetcode/servide/HelloService.java
package com.zetcode.service;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

@Service
public class HelloService {

    @Value("${app.message}")
    private String message;

    public String sayHello() {

        return message;
    }
}

HelloService returns a message retrieved from the application.properties file.

com/zetcode/Application.java
package com.zetcode;

import com.zetcode.config.AppConfig;
import com.zetcode.service.HelloService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.stereotype.Component;

@Component
public class Application {

    private static final Logger logger = LoggerFactory.getLogger(Application.class);

    public static void main(String[] args) {

        var ctx = new AnnotationConfigApplicationContext(AppConfig.class);

        var app = ctx.getBean(Application.class);
        app.run();

        ctx.close();
    }

    @Autowired
    private HelloService helloService;

    private void run() {

        logger.info("Calling hello service");
        logger.info(helloService.sayHello());

    }
}

The application prints a message to the console using HelloService.

$ mvn -q exec:java
17:50:54.118 INFO  com.zetcode.Application - Calling hello service
17:50:54.118 INFO  com.zetcode.Application - Hello there!

We run the application.

resources/appTest.properties
app.message=Testing hello message

The appTest.properties is specific for the testing.

com/zetcode/service/HelloServiceTest.java
package com.zetcode.service;

import com.zetcode.config.AppConfig;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.TestPropertySource;
import org.springframework.test.context.junit4.SpringRunner;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.junit.Assert.assertThat;

@RunWith(SpringRunner.class)
@ContextConfiguration(classes={HelloService.class})
@TestPropertySource("/appTest.properties")
public class HelloServiceTest {

    @Value("${app.message}")
    private String message;

    @Autowired
    private HelloService helloService;

    @Test
    public void testHelloMessage() {

        var message = helloService.sayHello();
        assertThat(message, equalTo(message));
    }
}

HelloServiceTest is used for testing the HelloService class.

@RunWith(SpringRunner.class)
@ContextConfiguration(classes={HelloService.class})
@TestPropertySource("/appTest.properties")
public class HelloServiceTest {

The test class is annotated with @RunWith(SpringRunner.class). The @ContextConfiguration defines class-level metadata which is used to determine how to load and configure an application context for integration tests. In addition, we provide custom test property file with @TestPropertySource.

@Value("${app.message}")
private String message;

We inject the message from the appTest.properties file.

@Autowired
private HelloService helloService;

We inject the HelloMessage service class. This is the class to be tested.

@Test
public void testHelloMessage() {

    var message = helloService.sayHello();
    assertThat(message, equalTo(message));
}

We test that the message from the service method equals to the injected string value.

$ mvn -q test

-------------------------------------------------------
    T E S T S
-------------------------------------------------------
Running com.zetcode.service.HelloServiceTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.489 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

We run the tests.

In this tutorial, we shown how to use SpringRunner to create tests in a Spring application. Spring MockMvc tutorial, Spring @PropertySource tutorial, Java tutorial.