---
id: "bug-1500"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "scheduler"
severity: "unknown"
timestamp: "2026-08-06T00:00:00Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 1
files: ["src/scheduler/testsuite/test_sim_event_loop.c"]
tags: ["scheduler-core", "task-11.2", "sim_loop.c", "test-fixture", "sched_record_stop", "ReplayEvent_body_endSession", "premature-termination-marker"]
related: []
legacy: true
---

# bug-1500: test_run_processes_multiple_sessions_in_order_and_no_longer_returns_enosys FAIL: Expected 5000 Was…

## Description
test_run_processes_multiple_sessions_in_order_and_no_longer_returns_enosys FAIL: Expected 5000 Was 743938186628040 (a raw-looking CLOCK_MONOTONIC nanosecond value, not the fixture's own beginRound).

## Environment
_Not recorded (migrated from buglog.json)._

## Reproduction
_Not recorded (migrated from buglog.json)._

## Root cause
The test's fixture-building helper called the real sched_record_start() THEN sched_record_stop() to produce a valid header+snapshot prefix (matching test_sim_startup.c's own write_valid_fixture() precedent), then re-opened the same path in append mode ('a') to hand-write additional ReplayEvent/ReplaySession messages after it. But sched_record_stop() (recording.c) unconditionally writes its OWN ReplayEvent{endSession} marker immediately after the snapshot as part of every completed recording (Req 5 AC 20) -- so the fixture already contained a premature end-of-stream marker BEFORE any of the test's own appended events/sessions. sched_sim_driver_run()'s event loop (sim_loop.c, task 11.2) correctly treats ReplayEvent{endSession} as the whole-stream termination signal and stopped reading right there, leaving sim->core's clock at its xce_sched_core_init() default (virtual_clock_base=0, speed_num=1, speed_den=1 -- AC 3's normal-mode row), so xce_core_now() returned an unfrozen, elapsed-wall-clock-driven value instead of the intended frozen 5000.

## Fix
Changed the fixture helper to call ONLY sched_record_start() (never sched_record_stop()), and return the STILL-OPEN FILE* (sched.record_file) so the test appends its own hand-built events/sessions directly onto the same open stream, ending with its own append_end_of_stream_marker() call, then fclose()s it directly -- bypassing sched_record_stop()'s real event/session-recording API entirely for this hand-built-fixture use case.

## Verification
_Not recorded (migrated from buglog.json)._

## References
_Not recorded (migrated from buglog.json)._