Do tests that run on Firebase test lab run parallel and not sequential

Question

I'm running UI instrumented tests using Espresso on Firebase test lab. Dose the tests execution is in parallel or sequential?

Answer 1

Espresso tests always run sequentially. It's impossible to run them in parallel on the same device because they may make use of the main thread for the app. In fact, with Test Orchestrator, the entire app will be created and torn down with each test to ensure that tests are fully hermetic.

If you need to shard your tests to run them in parallel on different devices, you'll need a special tool (such as Flank) to manage that.

Answer 2

If you implement cucumber on your espresso test, you can set in cucumber option in your instrumentation file for ordering test case sequentially.

@CucumberOptions(
    features = "features",
    tags = "@first-feature,@second-feature,@third-feature,@last-feature",
    glue = "package name")

like @Doug Stevenson answer, you can use Flank for parallel.