第三十四章. JaCoCo 插件

首先，请将 JaCoCo 插件应用于你想要计算代码覆盖率的项目中。
To get started, apply the JaCoCo plugin to the project you want to calculate code coverage for.

apply plugin: "jacoco"

如果你的项目同时也应用了 Java 插件，那么会创建一个名为 jacocoTestReport 的新任务，并且这个新任务依赖于 test 任务。该报告可以在 $buildDir/report/jacoco/test 中看到。默认情况下，会生成一个 HTML 报告。
If the Java plugin is also applied to your project, a new task named jacocoTestReport is created that depends on the test task. The report is available at $buildDir/reports/jacoco/test. By default, a HTML report is generated.

JaCoCo 插件添加一个类型为 JacocoPluginExtension，名为jacoco 的 project 扩展，这个扩展允许在你的构建中配置 JaCoCo 所使用的默认值。
The JaCoCo plugin adds a project extension named jacoco of type JacocoPluginExtension, which allows configuring defaults for JaCoCo usage in your build.

jacoco {
    toolVersion = "0.6.2.201302030002"
    reportsDir = file("$buildDir/customJacocoReportDir")
}

JacocoReport 任务可以生成不同格式的代码覆盖率报告。它实现了标准的 Gradle 类型 Reporting，并向外暴露了一个 JacocoReportsContainer 类型的报告容器。
The JacocoReport task can be used to generate code coverage reports in different formats. It implements the standard Gradle type Reporting and exposes a report container of type JacocoReportsContainer.

jacocoTestReport {
    reports {
        xml.enabled false
        csv.enabled false
        html.destination "${buildDir}/jacocoHtml"
    }
}

JaCoCo 插件添加了一个 JacocoTaskExtension 扩展到所有 Test 类型的任务中。这一扩展允许配置测试任务中的一些特定的 JaCoCo 属性。
The JaCoCo plugin adds a JacocoTaskExtension extension to all tasks of type Test. This extension allows the configuration of the JaCoCo specific properties of the test task.

test {
    jacoco {
        append = false
        destinationFile = file("$buildDir/jacoco/jacocoTest.exec")
        classDumpFile = file("$buildDir/jacoco/classpathdumps")
    }
}

虽然所有 Test 类型的任务会在应用 java 插件时自动增强以提供覆盖率信息，但是任何实现了 JavaForkOptions 的任务都可以通过 JaCoCo 插件得到增强。也就是说，任何 fork Java 进程的任务都可生成覆盖信息。
While all tasks of type Test are automatically enhanced to provide coverage information when the java plugin has been applied, any task that implements JavaForkOptions can be enhanced by the JaCoCo plugin. That is, any task that forks Java processes can be used to generate coverage information.

例如，你可以配置你的构建使用 application 插件来生成代码覆盖率。
For example you can configure your build to generate code coverage using the application plugin.

apply plugin: "application"
apply plugin: "jacoco"

mainClassName = "org.gradle.MyMain"

jacoco {
    applyTo run
}

task applicationCodeCoverageReport(type:JacocoReport){
    executionData run
    sourceSets sourceSets.main
}

application/
  build/
    jacoco/
      run.exec
    reports/jacoco/applicationCodeCoverageReport/html/
      index.html

对于同时也应用了 Java 插件的项目，JaCoCo 插件会自动添加以下任务：
For projects that also apply the Java Plugin, The JaCoCo plugin automatically adds the following tasks:

JaCoCo 插件添加了以下依赖配置：
The JaCoCo plugin adds the following dependency configurations: