feat(event): add invoice.issued and invoice.paid event contracts

order/order_test.go

@@ -28,3 +28,49 @@ func TestCreatedRoundTrip(t *testing.T) {
 		t.Errorf("line[0] mismatch: %+v", out.Lines[0])
 	}
 }
+
+func TestInvoiceIssuedRoundTrip(t *testing.T) {
+	in := InvoiceIssued{
+		OrderID:       "ord-1",
+		InvoiceNumber: "INV-000001",
+		CompanyID:     "comp-1",
+		CustomerEmail: "a@b.c",
+		AmountIncVat:  14995,
+		DueDate:       "2026-09-15",
+		OCRReference:  "00000139",
+		IssuedAtMs:    1234567890,
+	}
+	raw, err := in.Encode()
+	if err != nil {
+		t.Fatalf("encode: %v", err)
+	}
+	out, err := DecodeInvoiceIssued(raw)
+	if err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if out.InvoiceNumber != in.InvoiceNumber || out.OCRReference != in.OCRReference || out.AmountIncVat != in.AmountIncVat {
+		t.Fatalf("round-trip mismatch: got %+v, want %+v", out, in)
+	}
+}
+
+func TestInvoicePaidRoundTrip(t *testing.T) {
+	in := InvoicePaid{
+		OrderID:       "ord-1",
+		InvoiceNumber: "INV-000001",
+		CompanyID:     "comp-1",
+		AmountPaid:    14995,
+		PaidAtMs:      1234567990,
+	}
+	raw, err := in.Encode()
+	if err != nil {
+		t.Fatalf("encode: %v", err)
+	}
+	out, err := DecodeInvoicePaid(raw)
+	if err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if out.InvoiceNumber != in.InvoiceNumber || out.AmountPaid != in.AmountPaid {
+		t.Fatalf("round-trip mismatch: got %+v, want %+v", out, in)
+	}
+}
+