如何使用 Espresso 测试获取 Android 项目的覆盖率

Question

I used to write Android tests using Robotium and retrieve the coverage using Emma.

Recently I changed to use Espresso tests and I'm having troubles to retrieve coverage of Instrumentation tests. I can only retrieve coverage for Unit tests that use Robolectric. I'm currently using gradle and Jacoco to do that. The best tutorial I found which helped me to get to this point was: https://blog.gouline.net/2015/06/23/code-coverage-on-android-with-jacoco/

Is it possible to retrieve coverage of Espresso tests that use Android instrumentation?

Answer 1

The android gradle plugin has a built-in feature.

Just set testCoverageEnabled parameter to true in your build.gradle file:

android {
   buildTypes {
      debug {
         testCoverageEnabled = true
      }
   }
}

Then use:

./gradlew connectedCheck

or

./gradlew createDebugCoverageReport

It will produce a test coverage report in the directory of the module:

/build/outputs/reports/coverage/debug/

Just open the index.html

Example:

Answer 2

Coverage report in Android with Jacoco (Java Code Coverage)

Android Gradle plugin >=3.x

add the new Jacoco version in the classpath dependencies

project build.gradle file

buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
        classpath 'org.jacoco:org.jacoco.core:0.8.0'
    }
}

app build.gradle file

// app/build.gradle

apply plugin: 'com.android.application'
apply plugin: 'jacoco'

jacoco {
    toolVersion = '0.8.0'
}

tasks.withType(Test) {
    jacoco.includeNoLocationClasses = true
}

...

Create task eg jacocoTestReport

task jacocoTestReport(type: JacocoReport, dependsOn: ['testDebugUnitTest', 'createDebugCoverageReport']) {

    reports {
        xml.enabled = true
        html.enabled = true
    }

    def fileFilter = ['**/R.class', '**/R$*.class', '**/BuildConfig.*', '**/Manifest*.*', '**/*Test*.*', 'android/**/*.*']
    def debugTree = fileTree(dir: "$project.buildDir/intermediates/classes/debug", excludes: fileFilter)
    def mainSrc = "$project.projectDir/src/main/java"

    sourceDirectories = files([mainSrc])
    classDirectories = files([debugTree])
    executionData = fileTree(dir: project.buildDir, includes: [
            'jacoco/testDebugUnitTest.exec', 'outputs/code-coverage/connected/*coverage.ec'
    ])
}

Read more here

Android Gradle plugin <3.x
Android Gradle plugin >=3.x