Maven 单元测试

编写主代码

public class HelloWorld {

    public String sayHello() {
        return "Hello Maven!";
    }

}

测试代码

pom添加单元测试依赖:

<?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>org.pengxiaohe</groupId>
    <artifactId>maven-test</artifactId>
    <version>1.0-SNAPSHOT</version>

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

上述pom代码中有一个值为test的元素scope，scope为依赖范围，若依赖范围为test则表示该依赖只对测试有效，换句话说，测试代码中import Junit代码是没有问题的，但是如果在主代码中用import Junit代码，就会造成编译错误。如果不声明依赖范围，默认值是compile，表示依赖对主代码和测试代码都有效。
测试类：

import org.junit.Test;

import static org.junit.Assert.assertEquals;

public class TestHelloWorld {

    @Test
    public void testSayHello() {
        HelloWorld helloWorld = new HelloWorld();
        String sayHelloRes = helloWorld.sayHello();
        assertEquals("Hello Maven!", sayHelloRes);
    }
}

一个典型的单元测试包含三个步骤：

1. 准备测试类和测试数据
2. 执行要测试的行为；
3. 检查结果

执行测试

mvn clean test

执行结果：

[INFO] Scanning for projects…
[INFO]
[INFO] ————————————————————————
[INFO] Building maven-test 1.0-SNAPSHOT
[INFO] ————————————————————————
[INFO]
[INFO] — maven-clean-plugin:2.5:clean (default-clean) @ maven-test —
[INFO] Deleting /Users/pengxiaohe/private_project/common/maven-test/target
[INFO]
[INFO] — maven-resources-plugin:2.6:resources (default-resources) @ maven-test —
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] — maven-compiler-plugin:3.1:compile (default-compile) @ maven-test —
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 1 source file to /Users/pengxiaohe/private_project/common/maven-test/target/classes
[INFO]
[INFO] — maven-resources-plugin:2.6:testResources (default-testResources) @ maven-test —
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /Users/pengxiaohe/private_project/common/maven-test/src/test/resources
[INFO]
[INFO] — maven-compiler-plugin:3.1:testCompile (default-testCompile) @ maven-test —
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 1 source file to /Users/pengxiaohe/private_project/common/maven-test/target/test-classes
[INFO]
[INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ maven-test —

[INFO] Surefire report directory: /Users/pengxiaohe/private_project/common/maven-test/target/surefire-reports

T E S T S

——————————————————- Running com.pizi.helloworld.TestHelloWorld Tests run: 1, Failures: 0, Errors:
0, Skipped: 0, Time elapsed: 0.06 sec

Results :

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

[INFO]
———————————————————————— [INFO] BUILD SUCCESS [INFO]
———————————————————————— [INFO] Total time: 1.558 s [INFO] Finished at:

2018-03-03T23:53:11+08:00 [INFO] Final Memory: 17M/306M [INFO]

Maven在执行测试之前，它会先执行项目的主资源管理，主代码编译，测试资源管理、测试代码编译等工作，这是maven生命周期的一个特性。