     "period_start": 1234567890,
     "starting_balance": 0,
     "status": "open",
+    "status_transitions": {
+        "finalized_at": 1234567890,
+    },
     "subtotal": 0,
     "total": 0,
     "webhooks_delivered_at": 1234567890

    "closed": false,
    "currency": "usd",
    "customer": "cus_CCiTI4Tpghl0nK",
    "date": 1234567890,
    "default_source": null,
    "due_date": 1234567890,
    "finalized_at": 1234567890,
    "forgiven": false,
    "hosted_invoice_url": "https://pay.stripe.com/invoice/invst_zw7Gf743ihdarScjrVuMTtctoT",
    "invoice_pdf": "https://pay.stripe.com/invoice/invst_zw7Gf743ihdarScjrVuMTtctoT/pdf",

                XCTAssertEqual(invoice.closed, false)
                XCTAssertEqual(invoice.currency, .usd)
                XCTAssertEqual(invoice.customer, "cus_CCiTI4Tpghl0nK")
                XCTAssertEqual(invoice.created, Date(timeIntervalSince1970: 1234567890))
                XCTAssertEqual(invoice.defaultSource, nil)
                XCTAssertEqual(invoice.dueDate, Date(timeIntervalSince1970: 1234567890))
                XCTAssertEqual(invoice.statusTransitions?.finalizedAt, Date(timeIntervalSince1970: 1234567890))
                XCTAssertEqual(invoice.forgiven, false)
                XCTAssertEqual(invoice.hostedInvoiceUrl, "https://pay.stripe.com/invoice/invst_zw7Gf743ihdarScjrVuMTtctoT")
                XCTAssertEqual(invoice.invoicePdf, "https://pay.stripe.com/invoice/invst_zw7Gf743ihdarScjrVuMTtctoT/pdf")
