Jacoco code coverage 0% in Android-kotlin project

Question

I have been trying to implement Jacoco for code coverage in Android kotlin project. I used deafult android studio coverage tool but it was not reliable. So I tried to implement Jacoco but I am getting 0% code coverage even after tests are passing successfully.

0% Coverage -

Succesfull test run -

Here is the gradle script -

plugins {
id 'com.android.library'
id 'kotlin-android'
id 'jacoco'
}


android {
compileSdkVersion 30
buildToolsVersion "30.0.3"

defaultConfig {
    minSdkVersion 21
    targetSdkVersion 30
    versionCode 1
    versionName "1.0"

    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    consumerProguardFiles "consumer-rules.pro"
}

buildTypes {
    debug {
        debuggable true
        minifyEnabled false
        testCoverageEnabled true
    }
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
    }
}
compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
    jvmTarget = '1.8'
}
testOptions {
    unitTests.returnDefaultValues = true
}

}



dependencies {

implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
implementation 'androidx.core:core-ktx:1.5.0'
implementation 'androidx.appcompat:appcompat:1.3.0'
implementation 'com.google.android.material:material:1.3.0'
testImplementation 'junit:junit:4.+'
testImplementation 'org.mockito:mockito-core:3.11.2'

testImplementation 'org.mockito:mockito-inline:3.11.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

jacoco {
toolVersion = "0.8.5"
// Custom reports directory can be specfied like this:
// reportsDir = file("$buildDir/customJacocoReportDir")
}

tasks.withType(Test) {
jacoco.includeNoLocationClasses = true
jacoco.excludes = ['jdk.internal.*']
// see related issue https://github.com/gradle/gradle/issues/5184#issuecomment-457865951
}

project.afterEvaluate {

(android.hasProperty('applicationVariants')
        ? android.'applicationVariants'
        : android.'libraryVariants')
        .all { variant ->
            def variantName = variant.name
            def unitTestTask = "test${variantName.capitalize()}UnitTest"
            def androidTestCoverageTask = "create${variantName.capitalize()}CoverageReport"

            tasks.create(name: "${unitTestTask}Coverage", type: JacocoReport, dependsOn: [
                    "$unitTestTask",
                    "$androidTestCoverageTask"
            ]) {
                group = "Reporting"
                description = "Generate Jacoco coverage reports for the ${variantName.capitalize()} build"

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

                def excludes = [
                        // data binding
                        'android/databinding/**/*.class',
                        '**/android/databinding/*Binding.class',
                        '**/android/databinding/*',
                        '**/androidx/databinding/*',
                        '**/BR.*',
                        // android
                        '**/R.class',
                        '**/R$*.class',
                        '**/BuildConfig.*',
                        '**/Manifest*.*',
                        '**/*Test*.*',
                        'android/**/*.*',
                        // kotlin
                        '**/*MapperImpl*.*',
                        '**/*$ViewInjector*.*',
                        '**/*$ViewBinder*.*',
                        '**/BuildConfig.*',
                        '**/*Component*.*',
                        '**/*BR*.*',
                        '**/Manifest*.*',
                        '**/*$Lambda$*.*',
                        '**/*Companion*.*',
                        '**/*Module*.*',
                        '**/*Dagger*.*',
                        '**/*Hilt*.*',
                        '**/*MembersInjector*.*',
                        '**/*_MembersInjector.class',
                        '**/*_Factory*.*',
                        '**/*_Provide*Factory*.*',
                        '**/*Extensions*.*',
                        // sealed and data classes
                        '**/*$Result.*',
                        '**/*$Result$*.*'
                ]

                def javaClasses = fileTree(dir: variant.javaCompileProvider.get().destinationDir,
                        excludes: excludes)
                def kotlinClasses = fileTree(dir: "${buildDir}/tmp/kotlin-classes/${variantName}",
                        excludes: excludes)

                classDirectories.setFrom(files([
                        javaClasses,
                        kotlinClasses
                ]))

                def variantSourceSets = variant.sourceSets.java.srcDirs.collect { it.path }.flatten()
                sourceDirectories.setFrom(project.files(variantSourceSets))

                def androidTestsData = fileTree(dir: "${buildDir}/outputs/code_coverage/${variantName}AndroidTest/connected/", includes: ["**/*.ec"])

                executionData(files([
                        "$project.buildDir/jacoco/${unitTestTask}.exec",
                        androidTestsData
                ]))
            }

        }
}

Answer 1

Right now, for an android multimodule project with:

• jacoco 0.8.7
• gradle plugin 7.0.2

I am finding that if debug { testCoverageEnabled true } is set, jacoco produces no output for unit tests (eg testDebugUnitTest). Whereas if it is not, /build/jacoco/testDebugUnitTest.exec is created, with actual coverage data.

This is clearly a bug, but not sure what component it's in. It is bad because it means that it'll work for either device or unit tests, but not both at the same time.

Answer 2

What I remember is that only a specific version of jacoco is supported:

apply plugin: 'jacoco'
jacoco {
    toolVersion = '0.7.5.201505241946'
}

Answer 3

For anyone who still facing the issue:

It's an Android Gradle Plugin issue

Upgrade Android Gradle Plugin to 7.2.1 will do the fix.

Answer 4

I have struggled with this issue for 3 years across multiple projects, but I have a solution (or rather someone who resolved my issues).

The Android-Root-Coverage-Plugin can be used to combine both jUnit and instrumented tests in a Java and/or Kotlin multi module project without any great need to configure anything else. It resolved my following issues:

• Getting coverage in multi module project
• Incorrect coverage in Kotlin
• Combining both jUnit & Instrumented test coverage

It has been confirmed that the cause of my issues were due to a bug in the android gradle plugin and as of Aug, 2022 it has yet to be resolved.

Answer 5

It seems like that are issues when using hilt + jacoco in the same project, so probably why we don't get coverage... https://github.com/google/dagger/issues/2740

Answer 6

If you are using Hilt in your project, try adding build/intermediates/asm_instrumented_project_classes/<Product>Debug/ folder inside classDirectories in your Jacoco Task.

A related issue in issue tracker: https://issuetracker.google.com/issues/161300933#comment5

Answer 7

I assume you only have unit test and do not have any Android Instrument test??

If this is the case, after you run ./gradlew ${unitTestTask}Coverage . You should see the following file generated

Please absolutely avoid the coverage folder, that folder also contains a report, however, it is hard wired to only generate Android Instrument Test coverage.

If you click open the app/build/reports/jacoco folder

This xml report is the one generated from our jacoco gradle task. And It should contains both the Android Instrument test and unit test.

I enabled the html option from gradle task. And if I open the index.html in this jacoco folder. It is different result than the one generated from reports/coverage folder.

Also double check the unit test compile and run fine, otherwise it can get ignored and cause 0%