#18: implement SMTP Submission (587/465), SASL PLAIN/LOGIN auth and preflight diagnostics

services/protocols/internal/domain/entity/outbound_job_test.go

@@ -5,26 +5,50 @@ import (
 	"time"
 )
 
-func TestCalculateNextBackoff_SchedulesCorrectDelays(t *testing.T) {
+// PLAN.md section 6.3 defines the wait *before the next* attempt: after
+// attempt 1 fails the next try is +5 min, after attempt 3 it is +1 h together
+// with the delay DSN, and from the fifth try on the delay carries +/-20%
+// jitter. A zero delay after the first failure would hammer the destination in
+// a tight loop.
+func TestCalculateNextBackoff_FollowsRetryTable(t *testing.T) {
 	now := time.Now()
 	expiresAt := now.Add(5 * 24 * time.Hour)
 
-	// Attempt 2 -> +5 min
-	next, delayDsn, perm := CalculateNextBackoff(now, 2, expiresAt)
-	if perm || delayDsn || next.Sub(now) < 4*time.Minute {
-		t.Errorf("attempt 2 backoff mismatch: next=%v, delayDsn=%v, perm=%v", next, delayDsn, perm)
+	cases := []struct {
+		failedAttempt int
+		wantMin       time.Duration
+		wantMax       time.Duration
+		wantDelayDsn  bool
+	}{
+		{1, 5 * time.Minute, 5 * time.Minute, false},
+		{2, 15 * time.Minute, 15 * time.Minute, false},
+		{3, time.Hour, time.Hour, true},
+		{4, 96 * time.Minute, 144 * time.Minute, false},   // 2 h +/- 20%
+		{5, 192 * time.Minute, 288 * time.Minute, false},  // 4 h +/- 20%
+		{6, 384 * time.Minute, 576 * time.Minute, false},  // 8 h +/- 20%
+		{7, 576 * time.Minute, 864 * time.Minute, false},  // 12 h +/- 20%
+		{20, 576 * time.Minute, 864 * time.Minute, false}, // steady 12 h
 	}
 
-	// Attempt 4 -> +1 hr + delayDsn=true
-	next, delayDsn, perm = CalculateNextBackoff(now, 4, expiresAt)
-	if perm || !delayDsn || next.Sub(now) < 55*time.Minute {
-		t.Errorf("attempt 4 backoff mismatch: next=%v, delayDsn=%v, perm=%v", next, delayDsn, perm)
+	for _, tc := range cases {
+		next, delayDsn, perm := CalculateNextBackoff(now, tc.failedAttempt, expiresAt)
+		if perm {
+			t.Errorf("attempt %d: unexpected permanent failure", tc.failedAttempt)
+			continue
+		}
+		got := next.Sub(now)
+		if got < tc.wantMin || got > tc.wantMax {
+			t.Errorf("attempt %d: delay = %v, want between %v and %v", tc.failedAttempt, got, tc.wantMin, tc.wantMax)
+		}
+		if delayDsn != tc.wantDelayDsn {
+			t.Errorf("attempt %d: delayDsn = %v, want %v", tc.failedAttempt, delayDsn, tc.wantDelayDsn)
+		}
 	}
+}
 
-	// Expired -> permanent failure
-	expiredTime := now.Add(-1 * time.Hour)
-	_, _, perm = CalculateNextBackoff(now, 5, expiredTime)
-	if !perm {
-		t.Errorf("expected permanent failure for expired job")
+func TestCalculateNextBackoff_ExpiredJobIsPermanent(t *testing.T) {
+	now := time.Now()
+	if _, _, perm := CalculateNextBackoff(now, 5, now.Add(-time.Hour)); !perm {
+		t.Error("expected permanent failure for an expired job")
 	}
 }