Fix ending an already ended session

[jkasten2]

Description

One Line Summary

Fixes invalid REST API requests, when location is on, to both outcomes/measure and User updates with session_time being zero/missing in the background.

Details

This is only present when location sharing is enabled in the SDK (in addition to the app and end-user allowing it) and the end-user opens the app at any point after receiving a notification. This resulted in 400 errors in the outcomes/measure case and no-op User updates that wasting resources, the later doesn't depend on receiving notifications. The outcomes/measure is also additive as the bad requests are cached and retried on app open.

Motivation

These invalid and no op request put a lot of extra load on both the device and the OneSignal backend.

Scope

Session tracking only.

Testing

Unit testing

Added a new session test and update an existing one.

Manual testing

Tested on an Android 14 emulator with our example app.

Reproducing the issue:

1. Allowed location
2. Sent a notification to the device
3. Wait until background location update fired.
   • Modified SDK to a lower time so this takes far less than 10 minutes
4. Observed the invalid request of os__session_duration with no session_time sent and the 400 response.

Reproducing repeating bad cached values:

1. Reproduce the root issue noted above.
2. Cold restart the app
3. Observer the missing session_time being relayed.
4. Added migration logic and observed these requests are no longer replied.

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
• I have reviewed this PR myself, ensuring it meets each checklist item

---

This change is 

[jinliu9508]

Code looks good and the changed comments are proper. I have also played with the test unit to verify that the results are correct.

I just have one question that since isValid is false by default and will set to true after the endSession call in onFocus(), is it expected that the first endSession() call after the very first app focus will always return early and do nothing?

[jinliu9508]

Code looks good and the changed comments are proper. I have also played with the test unit to verify that the results are correct.

I just have one question that since isValid is false by default and will set to true after the endSession call in onFocus(), is it expected that the first endSession() call after the very first app focus will always return early and do nothing?

Please disregard the question here as it is now clear to me that the change is necessary to start a new session if app is cold started.