Fix the try on 8000b637 and review round 2: RunBatches takes its gap as a parameter instead of reading the var BatchGap, and no tell while unhealthy is checked as an exact count, not a before/after that a same-pass tell could hide behind (issue 1520, 1524)

modules/mesh-mail-reader/cmd/mesh-mail-reader/batch.go

@@ -283,20 +283,24 @@ func RunOneBatch(ctx context.Context, store Store, readText ReadTextFunc, judge
 	return recordOutcome(ctx, store, OutcomeOK, "", judgedAt)
 }
 
-// RunBatches is the loop the running module drives (main.go): pace batch starts at least BatchGap apart
+// RunBatches is the loop the running module drives (main.go): pace batch starts at least gap apart
 // (nextBatchWait), take at most MaxMailsPerBatch of the waiting mails in arrival order, run one batch at a
 // time, and after each one — win or lose — try the mail signal (SendSignal, tell.go, issue 1522; it is its
 // own no-op when there is nothing untold that matters, or the reader is unhealthy) — forever, until ctx is
-// done. Not unit-tested itself beyond compiling (go vet): 1520/AC1's pacing and AC2-AC5's one-batch
-// behaviour, and 1522's signal-sending, are each proven directly, on nextBatchWait, RunOneBatch and
-// SendSignal, in batch_test.go and tell_test.go.
-func RunBatches(ctx context.Context, store Store, readText ReadTextFunc, judge JudgeFunc, check MessengerCheck, tell Tell, now func() time.Time, sleep func(time.Duration), logf func(string, ...any)) {
+// done. gap is given explicitly (main.go's batchLoop passes the var BatchGap, which only a `-tags
+// integration` build ever shortens; TestThirtyWaitingMailsRunAsThreeBatchesAtLeast160sApart passes
+// MinBatchGap) so this function itself never reads that var — the try on 8000b637 found this test still
+// reading it (and so, compiled into the integration binary, pacing at the shortened 3s instead of 160s)
+// when RunBatches read BatchGap directly inside its own loop (review round 2, issue 1520). 1520/AC2-AC5's
+// one-batch behaviour and 1522's signal-sending are proven directly, on RunOneBatch and SendSignal, in
+// batch_test.go and tell_test.go.
+func RunBatches(ctx context.Context, store Store, readText ReadTextFunc, judge JudgeFunc, check MessengerCheck, tell Tell, now func() time.Time, sleep func(time.Duration), logf func(string, ...any), gap time.Duration) {
 	var lastStart time.Time
 	for {
 		if ctx.Err() != nil {
 			return
 		}
-		if wait := nextBatchWait(lastStart, now(), BatchGap); wait > 0 {
+		if wait := nextBatchWait(lastStart, now(), gap); wait > 0 {
 			sleep(wait)
 			continue
 		}