Add on-device instrumented tests to a project with Robolectric tests

I have an Android project which uses Robolectric for testing. The relevant parts of build.gradle look a bit like this:

apply plugin: 'robolectric'

robolectric {
    include '**/*Test.class'
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')

    androidTestCompile 'org.hamcrest:hamcrest-integration:1.1'
    androidTestCompile 'org.hamcrest:hamcrest-core:1.1'
    androidTestCompile 'org.hamcrest:hamcrest-library:1.1'
    androidTestCompile('junit:junit:4.12') {
        exclude module: 'hamcrest-core'
    }
    androidTestCompile('org.robolectric:robolectric:2.4') {
        exclude module: 'classworlds'
        exclude module: 'commons-logging'
        exclude module: 'httpclient'
        exclude module: 'maven-artifact'
        exclude module: 'maven-artifact-manager'
        exclude module: 'maven-error-diagnostics'
        exclude module: 'maven-model'
        exclude module: 'maven-project'
        exclude module: 'maven-settings'
        exclude module: 'plexus-container-default'
        exclude module: 'plexus-interpolation'
        exclude module: 'plexus-utils'
        exclude module: 'wagon-file'
        exclude module: 'wagon-http-lightweight'
        exclude module: 'wagon-provider-api'
    }
    androidTestCompile 'com.android.support:support-v4:21.0.3'
}

and all the Robolectric tests are in src/androidTest/java/my/package/*Test.java. This has all been working perfectly. I can run the tests as part of a normal Gradle build, or through IntelliJ's JUnit GUI.

Now I need to add some tests that can't use Robolectric and need to run on a real Android device. Given that I've already had to use the androidTest variant for my Robolectric tests, how can I add my instrumented tests to this project, and still allow the Robolectric tests to run without a device?

This is super outdated setup, I suggest:

1. Use latest stable android gradle plugin:

   buildscript {
     dependencies {
       classpath 'com.android.tools.build:gradle:2.1.0'
     }
   }
   

2. Remove Robolectric gradle plugin:

   //apply plugin: 'robolectric'
   
   //robolectric {
   //    include '**/*Test.class'
   //}
   

3. Move test sources to test folder

4. Change androidTestCompile to testCompile

Now you can run your tests with ./gradlew test<Flavour>DebugUnitTest. And you can add your instrumental tests to androidTest folder.

Consider also upgrade Robolectric to 3.1 version