如何使用 SpringExtension 让我的测试与 JUnit5 一起工作？答案

【问题标题】：How to get my test working with JUnit5 using SpringExtension?如何使用 SpringExtension 让我的测试与 JUnit5 一起工作？
【发布时间】：2020-03-10 19:44:22
【问题描述】：

我正在尝试使用 JUnit5 进行测试，但在自动连接的 restTemplate bean 上获得了 NullPointerException。

测试配置：

import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class TestConfig {   
    @Bean
    public RestTemplate restTemplate(RestTemplateBuilder builder) {
        return builder.build();
    }
}

使用 JUnit4 类：

import static org.junit.Assert.assertTrue;
import static org.junit.jupiter.api.Assertions.assertEquals;

import org.apache.commons.lang3.math.NumberUtils;
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.boot.autoconfigure.web.client.RestTemplateAutoConfiguration;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.web.client.RestTemplate;

import lombok.extern.log4j.Log4j2;

@RunWith(SpringRunner.class)
@SpringBootTest
@ContextConfiguration(classes = {TestConfig.class, RestTemplateAutoConfiguration.class})
@Log4j2
public class Test {

    @Value("${service.url.base}/security-marking/count")
    private String countUrl;

    @Autowired
    private RestTemplate restTemplate;

    @Test
    public void testCount() throws Exception {
        LOG.info(countUrl);
        ResponseEntity<String> response = restTemplate.getForEntity(countUrl, String.class);
        assertEquals(HttpStatus.OK, response.getStatusCode());
        assertTrue(NumberUtils.isDigits(response.getBody()));
        assertTrue(NumberUtils.toInt(response.getBody()) >= 0);
    }
}

调用 restTemplate.getForEntity(...) 时出现 NullPointerException 失败：

import static org.junit.Assert.assertTrue;
import static org.junit.jupiter.api.Assertions.assertEquals;

import org.apache.commons.lang3.math.NumberUtils;
import org.junit.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.springframework.*.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.AutoConfigurationPackage;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.test.context.junit.jupiter.SpringExtension;
import org.springframework.web.client.RestTemplate;

import lombok.extern.log4j.Log4j2;

@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = {TestConfig.class, RestTemplate.class})
@Log4j2
@AutoConfigurationPackage
public class Test {

    @Value("${service.url.base}/bob/count")
    private String countUrl;

    @Autowired
    private RestTemplate restTemplate;

    @Test
    public void testCount() throws Exception {
        LOG.info(countUrl);
        ResponseEntity<String> response = restTemplate.getForEntity(countUrl, String.class);
        assertEquals(HttpStatus.OK, response.getStatusCode());
        assertTrue(NumberUtils.isDigits(response.getBody()));
        assertTrue(NumberUtils.toInt(response.getBody()) >= 0);
    }
}

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>

    <parent>
        <!-- Your own application should inherit from spring-boot-starter-parent -->
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.5.RELEASE</version>
        <relativePath />
    </parent>

    <artifactId>api-integration</artifactId>
    <groupId>group.id</groupId>
    <name>Integration Test</name>
    <description>Integration Test</description>
    <version>0.0.1-SNAPSHOT</version>

    <properties>
        <main.basedir>${basedir}/..</main.basedir>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-integration</artifactId>
        </dependency>
        <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>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
        <!-- HELPERS -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

堆栈跟踪：

java.lang.NullPointerException
    at Test.testCount(Test.java:36)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

【问题讨论】：

您可以尝试使用新的 RestTemplate() 而不是使用 RestTemplateBuilder 来创建 bean 吗？
如果我这样做它仍然失败，因为它没有导入 application.yml 配置。
可能与您的实际错误无关，但在将测试类从 JUnit 4 重构为 JUnit 5 但仍从 JUnit 4 包中导入 @Test 注释时，我遇到了不同类型的异常。使用 import org.junit.jupiter.api.Test 而不是 import org.junit.Test
这就是问题所在。还必须从 TestConfig 中删除 restTemplate 方法。
您有来自 org.junit.Test 的注释，这是错误的。那行不通……

标签： java spring spring-boot maven

【解决方案1】：

米桑托普是正确的。我必须修复 @Test 的导入路径并从 TestConfig.java 中删除 restTemplate bean 定义方法。

修复 #1 - 修复导入和使用 RestTemplateAutoConfiguration：

将import org.junit.Test; 更改为import org.junit.jupiter.api.Test;

和

@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = {TestConfig.class, RestTemplateAutoConfiguration.class})
@Log4j2

修复 #2 - 修复导入并使用从 RestConfig 中移除 bean：

将import org.junit.Test; 更改为import org.junit.jupiter.api.Test;

和

@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = {TestConfig.class, RestTemplate.class})
@Log4j2
public class SecurityMarkingsTest {

import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class TestConfig {

//  @Bean
//  public RestTemplate restTemplate(RestTemplateBuilder builder) {
//      return builder.build();
//  }

}

【讨论】：