Empty Jacoco report for Android Espresso

Question

I am trying to get code coverage for my Android project using Espresso tests. However, Jacoco is giving me back a report saying that I don't cover anything. I made a demo app to highlight my problem and that is here .

If you don't want to go to Github to look at the project, here is the build.gradle file:

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

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "ninja.bryansills.jacocotest"
        minSdkVersion 16
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    packagingOptions {
        exclude 'LICENSE.txt'
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
        debug {
            testCoverageEnabled true
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.1.1'

    androidTestCompile 'com.android.support.test:runner:0.2'
    androidTestCompile 'com.android.support.test:rules:0.2'
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.1'
}

Answer 1

Based on the issue pointed out by Ligol, here is what worked for me.

Added custom test runner in androidTest

package com.example;

import android.os.Bundle;
import android.support.test.runner.AndroidJUnitRunner;
import android.util.Log;

import java.lang.reflect.Method;

public class AndroidJacocoTestRunner extends AndroidJUnitRunner {

    static {
        System.setProperty("jacoco-agent.destfile", "/data/data/"+BuildConfig.APPLICATION_ID+"/coverage.ec");
    }

    @Override
    public void finish(int resultCode, Bundle results) {
        try {
            Class rt = Class.forName("org.jacoco.agent.rt.RT");
            Method getAgent = rt.getMethod("getAgent");
            Method dump = getAgent.getReturnType().getMethod("dump", boolean.class);
            Object agent = getAgent.invoke(null);
            dump.invoke(agent, false);
        } catch (Throwable e) {
            Log.d("JACOCO", e.getMessage());
        }
        super.finish(resultCode, results);
    }
}

Used this test runner in app/build.gradle

android{
    ...
    defaultConfig {
      ....
      testInstrumentationRunner "com.example.AndroidJacocoTestRunner"
    }
}

Answer 2

Your problem might be related to this issue.

https://code.google.com/p/android/issues/detail?id=170607

Answer 3

我在三星设备上遇到了同样的问题，我没有改变任何东西，但改为HTC设备，我开始得到覆盖。用JaCoCo三星设备似乎有点可疑。

Answer 4

I advise everyone not to use a Samsung device while generating coverage reports. I tried everything to fix the 0 coverage issue and luckily changed my device to Redmi Note 5 Pro and voila the coverage starts showing. On doing some research and reading some articles I found Samsung give less freedom to its user to use their products for testing. Though you can do the testing on Samsung devices after rooting them.