Where is the test apk located in Android Project?

Question

For running tests, Android Studio/Gradle generates a test apk which performs tests on the app apk. Can anyone share where the test apk gets generated and the location inside the project?

Following is my app/build.gradle

apply plugin: 'com.android.application'

android {
   compileSdkVersion 25
   buildToolsVersion "25.0.2"
   defaultConfig {
      applicationId "com.ark.beacons_test"
      minSdkVersion 16
      targetSdkVersion 25
      versionCode 1
      versionName "1.0"
      testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
   }
   buildTypes {
      release {
         minifyEnabled false
         proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
      }
   }

   packagingOptions {
      exclude 'META-INF/LICENSE'
   }

}

dependencies {
   compile fileTree(include: ['*.jar,*.aar'], dir: 'libs')
   compile(name: 'android-lib', ext: 'aar')
   compile 'com.android.support:appcompat-v7:25.3.1'
   compile 'com.android.support.constraint:constraint-layout:1.0.2' 
   androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
    exclude group: 'com.android.support', module: 'support-annotations'
   })
   testCompile 'junit:junit:4.12'
}

Answer 1

The test apk is generated in rootProject/app/build/outputs/apk/ folder. But to generate the test.apk file, you have to add instrumented tests in src/androidTest folder, atleast one dummy test. Then run the tests on a device by right clicking in project explorer and then select "Run All Tests" or "Run Tests" -->

Once you run the tests, then and then only a test.apk file gets created in the above mentioned folder.