According to documentation, my understanding about free quota was it is apply per project thus if I have one account that has 2 project A and B and used all of the testing quota in project A then I can still perform test under project B without yet being charge until the quota reached as well.
Keep in mind that the free daily quotas for Firebase pricing plans are enforced per Firebase project, not per app or per user. If you haven't already, check to make sure you haven't exceeded the quota for your Firebase project (for example, if you ran tests on another app in your project).
Now other product such as Firebase Firestore and Storage quota is reset around midnight Pacific time. Does this apply to all Firebase services that has quota including Test Lab?
Firebase Test Lab quotas also reset at midnight Pacific time.
I suspect that this applies to all Firebase services because in general quotas are enforced by the same underlying service.