feat: backend service

backend/internal/notification/dispatcher_test.go

@@ -0,0 +1,45 @@
+package notification
+
+import (
+	"testing"
+	"time"
+)
+
+// TestRouteBackoffMonotonic locks the documented schedule:
+// attempt 1 == ~backoffBase, each subsequent attempt grows by
+// backoffFactor up to backoffMax. The check uses the lower bound of
+// the jitter window so the assertion is robust under random output.
+func TestRouteBackoffMonotonic(t *testing.T) {
+	t.Parallel()
+	lower := func(d time.Duration) time.Duration {
+		return time.Duration(float64(d) * (1 - backoffJitter))
+	}
+	upper := func(d time.Duration) time.Duration {
+		return time.Duration(float64(d) * (1 + backoffJitter))
+	}
+
+	cases := []struct {
+		attempt int32
+		want    time.Duration
+	}{
+		{attempt: 1, want: backoffBase},
+		{attempt: 2, want: time.Duration(float64(backoffBase) * backoffFactor)},
+		{attempt: 3, want: time.Duration(float64(backoffBase) * backoffFactor * backoffFactor)},
+	}
+	for _, tc := range cases {
+		got := routeBackoff(tc.attempt)
+		if got < lower(tc.want) || got > upper(tc.want) {
+			t.Fatalf("attempt=%d got=%s want ~%s (±%.0f%%)", tc.attempt, got, tc.want, backoffJitter*100)
+		}
+	}
+}
+
+// TestRouteBackoffCap asserts the schedule clamps at backoffMax.
+func TestRouteBackoffCap(t *testing.T) {
+	t.Parallel()
+	upper := time.Duration(float64(backoffMax) * (1 + backoffJitter))
+	got := routeBackoff(50)
+	if got > upper {
+		t.Fatalf("attempt=50 got=%s exceeds cap (max=%s)", got, backoffMax)
+	}
+}