How do I get a jacoco coverage report using Android gradle plugin 0.10.0 or higher?

Over the hundreds of times searching the answer to getting a coverage report, I finally found an exact answer what I want.

From the this blog post, I found that gradlew createDebugCoverageReport creates the jacoco coverage report.

Also, from the gradle plugin source code, the plugin uses jacoco 0.6.2.201302030002 by default. (therefore, jacoco version definition is not required if you are going to use a default version)

In summary, the ESSENTIAL steps to get a jacoco coverage report with Android gradle plugin are:

1. Android gradle plugin version 0.10.0 or higher (typically in your project's build.gradle)
2. add testCoverageEnabled true to the build type you want (i.e. debug)
3. run $ gradlew createDebugCoverageReport or gradlew connectedCheck to get a jacoco coverage report.

You can find your coverage report at the build/reports/coverage/{buildType}. (i.e. build/reports/coverage/debug for debug build)

(Add multi-flavor case from @odiggity's comment)

If your project uses multi-flavor configuration, use create{flavorName}CoverageReport instead. The coverage report will be generated at build/reports/coverage/{flavorName}/{buildType}.

Example for flavor krInternal with debug build type:

• Command: ./gradlew createKrInternalDebugCoverageReport
• Report is genarated at: build/reports/coverage/krInternal/debug

Tip :

Since you can only get a coverage report with the emulator and device with root permission, you'll get following error after running a command on the regular(non-rooted) device:

05:48:33 E/Device: Error during Sync: Permission denied                         
java.io.IOException: com.android.ddmlib.SyncException: Permission denied
    at com.android.builder.testing.ConnectedDevice.pullFile(ConnectedDevice.java:114)
    at com.android.builder.internal.testing.SimpleTestCallable.call(SimpleTestCallable.java:158)
    at com.android.builder.internal.testing.SimpleTestCallable.call(SimpleTestCallable.java:42)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
    at java.lang.Thread.run(Thread.java:695)   
Caused by: com.android.ddmlib.SyncException: Permission denied
    at com.android.ddmlib.SyncService.doPullFile(SyncService.java:511)
    at com.android.ddmlib.SyncService.pullFile(SyncService.java:320)
    at com.android.ddmlib.Device.pullFile(Device.java:849)
    at com.android.builder.testing.ConnectedDevice.pullFile(ConnectedDevice.java:107)
    ... 10 more                
:myDirections:connectedAndroidTest FAILED      

FAILURE: Build failed with an exception.

Travis-CI build script to get code coverage

Include this block in build.gradle, for all modules (library, sample, etc)

android {
    lintOptions {
        abortOnError false
    }
}

Below is the .travis-ci.yml file

language: android
jdk: oraclejdk8
sudo: required

android:
  components:
  # Uncomment the lines below if you want to
  # use the latest revision of Android SDK Tools
  - tools
  - platform-tools
  # The BuildTools version used by your project
  - build-tools-28.0.3
  # The SDK version used to compile your project
  - android-28
  - android-22
  - add-on
  # Additional components
  - extra-google-google_play_services
  - extra-android-support
  - extra-google-m2repository
  - extra-android-m2repository
  # Specify at least one system image,
  # if you need to run emulator(s) during your tests
  - sys-img-armeabi-v7a-android-22

  licenses:
  - 'android-sdk-preview-license-52d11cd2'
  - 'android-sdk-license-.+'
  - 'google-gdk-license-.+'

before_cache:
- rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
- rm -fr $HOME/.gradle/caches/*/plugin-resolution/

cache:
  directories:
    - $HOME/.gradle/caches/
    - $HOME/.gradle/wrapper/
    - $HOME/.android/build-cache

before_install:
- yes | sdkmanager "build-tools;28.0.3"

before_script:
- echo no | android create avd --force -n test -t android-22 --abi armeabi-v7a -c 100M
- emulator -avd test -no-audio -no-window &
- android-wait-for-emulator
- sleep 180
- adb devices
- adb shell input keyevent 82 &

script:
- ./gradlew build connectedCheck

after_success:
- bash <(curl -s https://codecov.io/bash)

I created an open source plugin for that.

Root build.gradle

apply plugin: "com.vanniktech.android.junit.jacoco"

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath 'com.vanniktech:gradle-android-junit-jacoco-plugin:0.3.0'
    }
}

Then simply execute

./gradlew jacocoTestReportDebug // or jacocoTestReportRelease

It'll run the JUnit tests and then give you the Jacoco output in xml and html form in the corresponding build directory for debug build type.

Have to add an answer instead of a comment since my reputation is lower than 50...

What I want to supplement is:

Google released new build tools fixing the nasty "VerifyError" (link) issue.

Please try to change your setting in gradle to use latest build tools if you encounter the "VerifyError" issue. For instance,

android {
    ......
    buildToolsVersion '21.1.1'
    .....
}

Since the 21.0.0 build tools is buggy, please use a version greater than 21.0.0. I use 21.1.1.