Android Studio Code Coverage for Java and Kotlin Apps

This guide shows how to generate code coverage for Java and Kotlin Android apps in the Android Studio IDE using the RKTracer tool, with three simple steps:

1. Enable the RKTracer tool and rebuild the application.
2. Test the instrumented application and save the coverage data.
3. Generate code coverage reports.

Code Coverage tool integration with Android Studio IDE

Install the RKTracer plugin into the Android Studio IDE. Go to the File menu, then Settings, then Plugin. Click the setting icon and select install plug-in from disk.

Select the RKTracer-Android-Plugin.jar file from the plugins folder. On Windows the path is:

C:\rktracer\share\rktracer-plugins

On Linux the path is:

/home/username/rktracer/share/rktracer-plugins

Select RKTracer-Android-Plugin.jar and restart the Android Studio IDE. After restarting, the Tools menu shows the RKTrace option to turn RKTracer ON or OFF or to generate reports.

Generate Code Coverage for Android App in Android Studio IDE

Step 1: Enable the RKTracer tool and rebuild the application

Enable code coverage from the IDE menu:

Tools > RKTracer ON

You can also enable RKTracer in command-line mode. Where you would normally run gradlew build, instead run:

rktracer gradle -on app/build.gradle
gradlew clean
gradlew build

Step 2: Test the instrumented application and save coverage data

Run your tests against the instrumented application. Capture the coverage data with adb logcat and pull the rk-coverage.txt file from the device:

adb logcat -c
adb logcat > rk-coverage.txt 2<&1
adb pull /data/data/com.example.widecolor/rk-coverage.txt

Step 3: Generate code coverage reports

Run the rkresults command to generate the HTML reports. The command is the same on Linux and Windows:

rkresults

After generating the reports, disable RKTracer with:

rktracer gradle -off app/build.gradle

Enable coverage for selected files

You can scope coverage to specific folders, files, or functions by editing rktracer.config.

Coverage for selected folders

To instrument source files from some folders while ignoring others, add the following to rktracer.config:

ignore *.java
instrument */power/* */core/* */keys/*
never */firmware_loader/* */lockdown/*

Coverage for selected functions

To generate coverage only for specific functions in specific files, edit rktracer.config:

ignore *.java
instrument *source-file-X.java *source-file-Y.java *source-file-Z.java
function-ignore *
function-instrument fun_X() fun_Y() fun_Z()

Next steps

Once your Android app reports coverage, the same RKTracer workflow applies across other build systems and IDEs. Browse the rest of the documentation, or read more about how RKTracer measures coverage through MC/DC.