No error still Android Studio says "no tests were found"

Question

I am trying to write an instrumentation test for my MainActivity. I followed the answers given here. Still Android Studio cannot find any tests. I have the class ApplicationTest.java in the androidTest folder. Here's the contents of the class:

package com.example.monicamarcus.mymusicplayer

import android.app.Activity;
import android.test.ActivityInstrumentationTestCase2;
import com.example.monicamarcus.mymusicplayer.MainActivity;

public class ApplicationTest extends ActivityInstrumentationTestCase2<MainActivity> { 
    public ApplicationTest() {
        super(MainActivity.class);
    }

    public void testNextTrackButton() throws Exception {
        Activity activity = getActivity();

        Button nextButton = (Button) activity.findViewById(R.id.nextTrackBt);
        activity.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                nextButton.performClick();
                assertTrue(currentPosition < songList.size());
            }});
        activity.finish();
    }
}

What is wrong with this test class? Or with the tests? I don't get any error, it just does not find any test to run. After I run the ApplicationTest the output ends with the following lines:

Running tests
Test running startedFinish
Empty test suite.

Here's the build.gradle file for the app:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "com.example.monicamarcus.mymusicplayer"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        testApplicationId "app.src.androidTest.java.com.example.monicamarcus.mymusicplayer"
        testInstrumentationRunner "android.test.InstrumentationTestRunner"
    }
    buildTypes {
        debug {
            minifyEnabled false
        }
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

android {
    useLibrary 'org.apache.http.legacy'
}

android {

    sourceSets {

        androidTest {
            java.srcDirs = ['androidTest/java']
        }

    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.1'
    androidTestCompile 'junit:junit:4.12'
}

Here's the output of the test run:

Testing started at 1:56 PM ...
Target device: gt_i8190n-4790068ee9a750c6
Installing APK: /Users/monicamarcus/AndroidStudioProjects/MyMusicPlayer/app/build/outputs/apk/app-debug.apk
Uploading file to: /data/local/tmp/com.example.monicamarcus.mymusicplayer
Installing com.example.monicamarcus.mymusicplayer
DEVICE SHELL COMMAND: pm install -r "/data/local/tmp/com.example.monicamarcus.mymusicplayer"
pkg: /data/local/tmp/com.example.monicamarcus.mymusicplayer
Success


Installing APK: /Users/monicamarcus/AndroidStudioProjects/MyMusicPlayer/app/build/outputs/apk/app-debug-androidTest-unaligned.apk
Uploading file to: /data/local/tmp/app.src.androidTest.java.com.example.monicamarcus.mymusicplayer
Installing app.src.androidTest.java.com.example.monicamarcus.mymusicplayer
DEVICE SHELL COMMAND: pm install -r "/data/local/tmp/app.src.androidTest.java.com.example.monicamarcus.mymusicplayer"
pkg: /data/local/tmp/app.src.androidTest.java.com.example.monicamarcus.mymusicplayer
Success


Running tests
Test running startedFinish
Empty test suite.

After I made some changes (I can publish them if anybody is interested) the result of running the instrumentation test class read as follows: "Running tests. Test running started. Test running failed: No test results. Empty test suite." Nobody has experience with these kind of tests?

Answer 1

In build.gradle, testApplicationId looks very strange. I would remove this and testInstrumentationRunner. The default values should be fine. Specifically, if you do not specify testApplicationId, it will be created by appending ".test" to your applicationId.