Add regression test for retry task ID reuse

[andystaples]

Summary

• reproduce the v1 retry/fan-out sequence reported in Orchestration silently hangs after CallActivityWithRetry retry when next yield issues new tasks (TaskEventId reuse?) Azure/azure-functions-durable-python#603 through the 2.x Azure Functions worker transport
• verify the retry retains its original task ID while the retry timer advances the gRPC action sequence
• verify the subsequent 13-task fan-out receives distinct IDs and completes successfully

Validation

• python -m pytest tests/azure-functions-durable/test_worker_compat.py -q
• python -m flake8 tests/azure-functions-durable

[Copilot]

Pull request overview

Adds a regression test to the Azure Functions Durable worker compatibility suite to reproduce the retry + fan-out sequence from Azure/azure-functions-durable-python#603 and assert correct task ID behavior through the 2.x worker transport path.

Changes:

• Added a new end-to-end-style worker test that simulates history event replays for an activity retry (with timer) followed by a 13-task fan-out.
• Validates retry task ID reuse and that subsequent fan-out tasks are assigned distinct IDs and complete successfully.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

tests/azure-functions-durable/test_worker_compat.py:188

• The test builds timer_events (passed as newEvents) including new_timer_created_event(...). In existing executor tests, TimerCreated is treated as a past event (it reflects the prior CreateTimer action being committed to history) and only TimerFired is a new event. Keeping TimerCreated in newEvents can make this test diverge from real host history ordering and potentially mask regressions.

    timer_events = [
        helpers.new_timer_created_event(2, retry_at),
        helpers.new_orchestrator_started_event(retry_at),
        helpers.new_timer_fired_event(2, retry_at),
    ]

[berndverst]

Reviewed the retry/timer replay and subsequent fan-out allocation through the Azure Functions worker transport. The test asserts reuse of the original activity ID, advances the timer/action sequence without collisions, completes the 13-task fan-out, and rejects a retry-ID reallocation mutation. No actionable issues found.