https://github.com/googlesamples/android-testing-templates/tree/master/AndroidTestingBlueprint#running-instrumentation-tests says:

In Android Studio

• In the Build Variants window, make sure the Android Instrumentation Tests option is selected.
• Open a Instrumentation test class like EspressoTest.java or UiAutomatorTest.java
• Right click on the class and Run as Android Test.

For me (Android Studio 2.3.3 and 3 beta 6) there is no selection for this in "Build Variants".
On right clicking I also don't get "Run as ..." as an option, only "Run '...'".

What is the current equivalent for these instructions?