Android unit tests run on your device or in an emulator. They're located in the blocklytest directory. You can run the tests from the command line using gradle from the repository root:
blockly-android$ ./gradlew cC
Or, for more succinct output:
blockly-android$ ./gradlew -q cC
If the tests can't find your device or emulator, you'll get the following error message:
* What went wrong: Execution failed for task ':blocklytest:connectedDebugAndroidTest'. > com.android.builder.testing.api.DeviceException: No connected devices!
adb devices and your emulator or device's connections.
Android Studio can also run the tests. In the Project subwindow, using the
Project tree view, right-click the
blocklytest module and select Run.
You can also run individual test cases by similarly right-clicking the test file
and selecting Run.
Android Studio presents a dialog to select a connected device or start an emulator.