Gradle项目构建报错：Jacoco代码行覆盖率未达最低要求求助

我正在学习编写测试用例以理解相关机制，构建Gradle项目时碰到如下错误：

Rule violated for bundle java-gradle-examples: lines covered ratio is 0.0, but expected minimum is 0.5

我的Gradle配置（build.gradle） #

plugins {
    id 'java'
    id 'jacoco'
}

group = 'pl.something'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '16'

repositories {
    mavenCentral()
}

dependencies {
    implementation group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.6'
}

dependencies {
    compileOnly 'org.projectlombok:lombok:1.18.24'
    annotationProcessor 'org.projectlombok:lombok:1.18.24'

    testCompileOnly 'org.projectlombok:lombok:1.18.24'
    testAnnotationProcessor 'org.projectlombok:lombok:1.18.24'

    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.2'

    testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-params', version:'5.0.0-M4'
}

test {
    useJUnitPlatform()
    testLogging {
        events "passed", "skipped", "failed"
    }
}
test {
    useJUnitPlatform()
    testLogging {
        events "skipped", "failed"
    }
    finalizedBy jacocoTestReport
}
jacoco {
    toolVersion = "0.8.7"
}
jacocoTestReport {
    dependsOn test
    reports {
        xml.required = false
        csv.required = false
        html.outputLocation = layout.buildDirectory.dir('jacocoReports')
    }
}
jacocoTestCoverageVerification {
    violationRules {
        rule {
            limit {
                counter = 'LINE'
                value = 'COVEREDRATIO'
                minimum = 0.5
            }
        }
    }
}
check.dependsOn jacocoTestCoverageVerification

测试类代码 #

@Test
void add() {
    int left = 2;
    int right = 1;
    int expected = 3;

    Integer result = left + right;
    Assertions.assertEquals(expected, result);
}

@Test
void subtract() {
    int left = 2;
    int right = 1;
    int expected = 1;

    Integer result = left - right;
    Assertions.assertEquals(expected, result);
}

@Test
void multiply() {
    int left = 2;
    int right = 1;
    int expected = 2;

    Integer result = left * right;
    Assertions.assertEquals(expected, result);
}

@Test
@Disabled("I disabled this test for example")
void divide() {
    int left = 2;
    int right = 1;
    int expected = 2;

    Integer result = left / right;
    Assertions.assertEquals(expected, result);
}

主类代码 #

public class Main {

    public static void main(String[] args) {
        System.out.println(Calculator.add(1, 2));
        Calculator calculator = new Calculator();
        Calculator.substract(5, 3);
    }

}

问题原因及解决办法 #

1. 测试未覆盖业务代码：你的测试只是直接做数值计算，完全没调用Calculator类的方法，Jacoco检测不到任何业务代码被执行，所以覆盖率为0。
2. 重复配置test任务：build.gradle里写了两个test块，后面的会覆盖前面的配置，虽然不影响覆盖率，但建议合并。

具体修复步骤：

• 修改测试类，调用真实业务方法：
  把测试方法改成调用Calculator的对应方法，比如add测试：

  @Test
  void add() {
      int left = 2;
      int right = 1;
      int expected = 3;
  
      Integer result = Calculator.add(left, right); // 调用Calculator的add方法
      Assertions.assertEquals(expected, result);
  }
  

  其他测试方法同理，替换为调用Calculator的subtract（注意主类里拼写是substract，需和测试调用保持一致）、multiply方法。

• 合并test任务配置：
  将两个test块合并成一个：

  test {
      useJUnitPlatform()
      testLogging {
          events "passed", "skipped", "failed"
      }
      finalizedBy jacocoTestReport
  }
  

• 校验Calculator类的方法：确保Calculator类存在对应的静态/实例方法，保证测试能正常调用执行。

完成上述修改后，重新运行./gradlew check，Jacoco就能检测到代码覆盖，只要覆盖率达到50%以上就不会再报错。

内容的提问来源于stack exchange，提问作者Pp1