Added scheduler_test.go with 8 test cases covering all previously untested
security-critical code paths from PR #90:
TestLastTickAt_zero — zero time before first tick
TestHealthy_beforeStart — false on fresh scheduler (zero lastTickAt)
TestHealthy_freshTick — true when lastTickAt == now
TestHealthy_stale — false when lastTickAt is 3×pollInterval ago
TestComputeNextRun_valid — "0 * * * *" / UTC returns top-of-hour future time
TestComputeNextRun_invalid — unparseable expression returns non-nil error
TestComputeNextRun_invalidTimezone — unrecognised IANA zone returns non-nil error
TestPanicRecovery — panicProxy crashes ProxyA2ARequest; scheduler
goroutine recovers and remains Healthy
To support these tests, scheduler.go gained four changes (minimal surface):
1. Added mu sync.RWMutex, lastTickAt time.Time, and tickInterval time.Duration
fields to Scheduler. tickInterval defaults to pollInterval so production
behaviour is unchanged; tests can override it directly.
2. Added LastTickAt() and Healthy() methods with read-lock protection.
3. tick() now records lastTickAt after wg.Wait() — a single atomic write under
the mutex, no hot-path cost.
4. fireSchedule() got a deferred recover() so a panicking A2A proxy cannot
crash the goroutine pool. Without this, TestPanicRecovery itself crashes
the test binary — the test passing proves recovery is in place.
Bug fix: ComputeNextRun previously silently fell back to UTC on an invalid
timezone; it now returns a non-nil error. The schedules handler already
validates the timezone before calling ComputeNextRun so this is a no-op for
callers, but it makes the contract explicit and testable.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
140ae9ebee