#13: implement Outbound Queue, Retry Backoff Engine & DSN Bounce Generator (RFC 3464)

services/protocols/internal/domain/valueobject/dsn_bounce_test.go

@@ -0,0 +1,36 @@
+package valueobject
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBuildDsnReport_PreventsBounceLoopForEmptySender(t *testing.T) {
+	_, isLoop := BuildDsnReport(DsnActionFailed, "", "user@external.test", "msg123", "550 User unknown")
+	if !isLoop {
+		t.Errorf("expected loop prevention for empty sender")
+	}
+
+	_, isLoop = BuildDsnReport(DsnActionFailed, "<>", "user@external.test", "msg123", "550 User unknown")
+	if !isLoop {
+		t.Errorf("expected loop prevention for <> sender")
+	}
+}
+
+func TestBuildDsnReport_GeneratesValidMIME(t *testing.T) {
+	payload, isLoop := BuildDsnReport(DsnActionFailed, "sender@local.test", "recipient@remote.test", "msg123", "550 User unknown")
+	if isLoop || payload == nil {
+		t.Fatalf("unexpected loop signal for valid sender")
+	}
+
+	raw := string(payload)
+	if !strings.Contains(raw, "Content-Type: multipart/report; report-type=delivery-status") {
+		t.Errorf("missing multipart/report header: %s", raw)
+	}
+	if !strings.Contains(raw, "Action: failed") {
+		t.Errorf("missing Action: failed: %s", raw)
+	}
+	if !strings.Contains(raw, "Diagnostic-Code: smtp; 550 User unknown") {
+		t.Errorf("missing Diagnostic-Code: %s", raw)
+	}
+}