edr-platform/apps/edr-freight-api/src/modules/eims/eims-invoice-registration.service.spec.ts

import { BadRequestException, ConflictException } from "@nestjs/common";
import { ConfigService } from "@nestjs/config";
import { DataSource } from "typeorm";

import { EimsConfig } from "../../config/eims.config";
import { Invoice } from "../billing/entities/invoice.entity";
import { EimsInvoiceRequest } from "../billing/eims-invoice.mapper";
import { eimsInvoiceConfig } from "./eims-test-fixtures";
import { NotificationInboxService } from "../notification-inbox/notification-inbox.service";
import { NotificationsService } from "../notifications/notifications.service";
import { EimsAuthService } from "./eims-auth.service";
import { EimsClientService } from "./eims-client.service";
import { EimsApiException } from "./eims.errors";
import { EimsInvoiceRegistrationService } from "./eims-invoice-registration.service";
import { EimsSystemState } from "./entities/eims-system-state.entity";
import { EimsInvoiceStatus } from "./eims-registration.types";

const SYSTEM_NUMBER = "B0360154BA";
const INVOICE_ID = "11111111-1111-4111-8111-111111111111";
const OTHER_INVOICE_ID = "22222222-2222-4222-8222-222222222222";
const IRN = "9fe9bbbece6ab76c112b617534e6aac7aa8b819d5be79f4d3d088ed2e887b2e0";

const config = (over: Partial<EimsConfig["invoice"]> = {}): EimsConfig =>
  ({
    enabled: true,
    baseUrl: "https://core.mor.gov.et",
    clientId: "cid",
    clientSecret: "secret",
    apiKey: "key",
    tin: "0000034558",
    systemNumber: SYSTEM_NUMBER,
    systemType: "SYS",
    privateKeyPath: "/dev/null",
    certificatePath: "/dev/null",
    httpTimeoutMs: 30_000,
    tokenSkewMs: 45_000,
    invoice: eimsInvoiceConfig(over),
  }) as EimsConfig;

const invoiceRow = (over: Partial<Invoice> = {}): Invoice =>
  ({
    id: INVOICE_ID,
    invoiceNumber: "INV-20260807-00042",
    currency: "ETB",
    issuedAt: new Date(2026, 7, 7, 9, 5, 3),
    totalAmount: "10000.00",
    eimsStatus: EimsInvoiceStatus.NotSubmitted,
    eimsIrn: null,
    eimsInvoiceCounter: null,
    eimsSubmittedAt: null,
    eimsAckDate: null,
    eimsLastError: null,
    company: {
      name: "ABC Trading PLC",
      tin: "0999930000",
      vatNumber: "123475885858",
      phone: "0912345678",
      email: "buyer@abc.et",
      region: "13",
      zone: "SHA",
      woreda: "574",
      kebele: "03",
      houseNo: "NEW",
      country: "Ethiopia",
    },
    ...over,
  }) as unknown as Invoice;

const LINES = [
  {
    chargeType: "RAIL_FREIGHT",
    description: "Addis to Djibouti",
    quantity: "1.00",
    unitRate: "10000.00",
    amount: "10000.00",
  },
];

/**
 * In-memory stand-in for the two locked rows. `update` merges, `createQueryBuilder(...).getOne()`
 * returns the live object — enough to assert ordering, values and the reservation lifecycle without
 * a database.
 */
class FakeDb {
  invoices = new Map<string, Invoice>();
  state: EimsSystemState | null = null;
  /** Runs before every transaction body, to simulate a concurrent writer. */
  onTransaction: (() => void) | null = null;
  /** `sendCompanyChannels`'s contact lookup, when a test needs it non-empty. */
  companyContact: { phone: string | null; email: string | null } | null = null;

  constructor(invoices: Invoice[], state?: Partial<EimsSystemState>) {
    for (const inv of invoices) this.invoices.set(inv.id, inv);
    this.state = {
      id: "state-1",
      systemNumber: SYSTEM_NUMBER,
      nextInvoiceCounter: 7,
      nextDocumentNumber: 5,
      previousIrn: null,
      inFlightInvoiceId: null,
      inFlightCounter: null,
      inFlightDocumentNumber: null,
      blockedReason: null,
      ...state,
    } as EimsSystemState;
  }

  private manager = {
    createQueryBuilder: (entity: unknown) => {
      const isInvoice = entity === Invoice;
      let id: string | undefined;
      const builder = {
        setLock: () => builder,
        where: (_clause: string, params: Record<string, string>) => {
          id = params.invoiceId ?? params.systemNumber;
          return builder;
        },
        getOne: async () => (isInvoice ? (this.invoices.get(id!) ?? null) : this.state),
      };
      return builder;
    },
    findOne: async (_entity: unknown, options: { where: { id: string } }) =>
      this.invoices.get(options.where.id) ?? null,
    update: async (entity: unknown, id: string, patch: Record<string, unknown>) => {
      if (entity === Invoice) Object.assign(this.invoices.get(id)!, patch);
      else Object.assign(this.state!, patch);
    },
    query: async () => [],
    getRepository: () => ({
      findOne: async (options: { where: { id: string } }) =>
        this.invoices.get(options.where.id) ?? null,
    }),
  };

  asDataSource(): DataSource {
    return {
      manager: this.manager,
      getRepository: this.manager.getRepository,
      query: async (sql: string) => {
        if (sql.includes("eims_system_state")) {
          return [{ in_flight_invoice_id: this.state?.inFlightInvoiceId ?? null }];
        }
        if (sql.includes("freight.companies")) return this.companyContact ? [this.companyContact] : [];
        return LINES;
      },
      transaction: async (body: (m: unknown) => Promise<unknown>) => {
        this.onTransaction?.();
        return body(this.manager);
      },
    } as unknown as DataSource;
  }
}

/** The source system comes from the access token, so the service is handed a session, not config. */
const SESSION = { systemNumber: SYSTEM_NUMBER, systemType: "SYS" };

const build = (
  db: FakeDb,
  postSigned: jest.Mock,
  cfg: EimsConfig = config(),
  postBearer: jest.Mock = jest.fn(),
  getSessionContext: jest.Mock | undefined = undefined,
  notify: jest.Mock = jest.fn().mockResolvedValue(undefined),
  directSend: jest.Mock = jest.fn().mockResolvedValue(undefined),
) =>
  new EimsInvoiceRegistrationService(
    db.asDataSource(),
    { get: () => cfg } as unknown as ConfigService,
    { postSigned, postBearer } as unknown as EimsClientService,
    {
      getSessionContext: getSessionContext ?? jest.fn().mockResolvedValue(SESSION),
    } as unknown as EimsAuthService,
    { notify } as unknown as NotificationInboxService,
    { directSend } as unknown as NotificationsService,
  );

/**
 * Document number the fixtures register under; `/v1/verify` must echo it back.
 *
 * A plain integer, not our `invoiceNumber`: MoR validates the field against
 * `^(0|[1-9][0-9]{0,8})$`. It is allocated from `nextDocumentNumber` above.
 */
const DOCUMENT_NUMBER = "5";

/**
 * `/v1/verify` success. The response spells the reference `Irn` while the request sends lowercase
 * `irn`.
 *
 * The fixture is deliberately *coherent* — same IRN on both sides. The supplied Postman collection
 * pairs a saved request and a saved response whose literal IRNs disagree, which is an artefact of
 * the mock rather than gateway behaviour; asserting against that inconsistency would encode the
 * mock's bug as a requirement. Resolution requires the returned `Irn` to match the one asked for,
 * and these fixtures exercise that honestly.
 */
const verifyResponse = (over: Record<string, unknown> = {}) => ({
  statusCode: 200,
  message: "SUCCESS",
  body: {
    Irn: IRN,
    TransactionType: "B2B",
    DocumentDetails: { Type: "INV", DocumentNumber: DOCUMENT_NUMBER, Date: "07-08-2026T09:05:03" },
    Version: "1",
    ...over,
  },
});

const okResponse = (irn = IRN, over: Record<string, unknown> = {}) => ({
  statusCode: 200,
  message: "SUCCESS",
  body: { irn, ackDate: "2026-08-07T09:05:03Z[Etc/UTC]", ...over },
});

const apiError = (kind: string, status?: number) =>
  new EimsApiException(kind as never, `EIMS register failed (${status ?? "-"})`, status);

describe("EimsInvoiceRegistrationService.registerInvoiceWithEims", () => {
  it("registers, persists the IRN and advances the chain", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn().mockResolvedValue(okResponse());

    const view = await build(db, postSigned).registerInvoiceWithEims(INVOICE_ID);

    expect(postSigned).toHaveBeenCalledTimes(1);
    expect(postSigned.mock.calls[0][0]).toBe("/v1/register");
    expect(view).toMatchObject({
      eimsStatus: EimsInvoiceStatus.Registered,
      eimsIrn: IRN,
      eimsInvoiceCounter: 7,
      eimsAckDate: "2026-08-07T09:05:03Z[Etc/UTC]",
    });
    expect(db.state).toMatchObject({
      previousIrn: IRN,
      nextInvoiceCounter: 8,
      inFlightInvoiceId: null,
      inFlightCounter: null,
      blockedReason: null,
    });
  });

  it("persists signedQR alongside the IRN", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn().mockResolvedValue(okResponse(IRN, { signedQR: "signed-qr-payload" }));

    const view = await build(db, postSigned).registerInvoiceWithEims(INVOICE_ID);

    expect(view.eimsSignedQr).toBe("signed-qr-payload");
    expect(db.invoices.get(INVOICE_ID)?.eimsSignedQr).toBe("signed-qr-payload");
  });

  it("leaves eimsSignedQr null when the gateway does not return one", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn().mockResolvedValue(okResponse());

    const view = await build(db, postSigned).registerInvoiceWithEims(INVOICE_ID);

    expect(view.eimsSignedQr).toBeNull();
  });

  it("notifies the buyer company on a successful registration, without blocking the result", async () => {
    const db = new FakeDb([invoiceRow({ companyId: "company-1" } as Partial<Invoice>)]);
    db.companyContact = { phone: "+251911000000", email: "buyer@abc.et" };
    const directSend = jest.fn().mockResolvedValue(undefined);
    const postSigned = jest.fn().mockResolvedValue(okResponse());

    const view = await build(db, postSigned, config(), jest.fn(), undefined, undefined, directSend)
      .registerInvoiceWithEims(INVOICE_ID);

    expect(view.eimsStatus).toBe(EimsInvoiceStatus.Registered);
    expect(directSend).toHaveBeenCalledWith("sms", "+251911000000", expect.stringContaining(IRN));
    expect(directSend).toHaveBeenCalledWith("email", "buyer@abc.et", expect.stringContaining(IRN));
  });

  it("does not fail registration when the buyer notification itself fails", async () => {
    const db = new FakeDb([invoiceRow({ companyId: "company-1" } as Partial<Invoice>)]);
    db.companyContact = { phone: "+251911000000", email: null };
    const directSend = jest.fn().mockRejectedValue(new Error("sms provider down"));
    const postSigned = jest.fn().mockResolvedValue(okResponse());

    const view = await build(db, postSigned, config(), jest.fn(), undefined, undefined, directSend)
      .registerInvoiceWithEims(INVOICE_ID);

    expect(view.eimsStatus).toBe(EimsInvoiceStatus.Registered);
  });

  it("sends the exact reserved counter and previous IRN to the mapper", async () => {
    const db = new FakeDb([invoiceRow()], { nextInvoiceCounter: 42, previousIrn: "PRIOR-IRN" });
    const postSigned = jest.fn().mockResolvedValue(okResponse());

    await build(db, postSigned).registerInvoiceWithEims(INVOICE_ID);

    const request = postSigned.mock.calls[0][1] as EimsInvoiceRequest;
    expect(request.SourceSystem.InvoiceCounter).toBe(42);
    expect(request.ReferenceDetails.PreviousIrn).toBe("PRIOR-IRN");
    expect(request.DocumentDetails.DocumentNumber).toBe(DOCUMENT_NUMBER);
    expect(request.SourceSystem.SystemNumber).toBe(SYSTEM_NUMBER);
  });

  it("takes SourceSystem from the token session, not from configuration", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn().mockResolvedValue(okResponse());
    // Config disagrees on purpose: only the session may reach the wire.
    const cfg = config();
    (cfg as { systemNumber: string }).systemNumber = "CONFIG-ONLY";
    (cfg as { systemType: string }).systemType = "MAN";

    await build(
      db,
      postSigned,
      cfg,
      jest.fn(),
      jest.fn().mockResolvedValue({ systemNumber: "FROM-TOKEN", systemType: "POS" }),
    ).registerInvoiceWithEims(INVOICE_ID);

    const request = postSigned.mock.calls[0][1] as EimsInvoiceRequest;
    expect(request.SourceSystem.SystemNumber).toBe("FROM-TOKEN");
    expect(request.SourceSystem.SystemType).toBe("POS");
  });

  it("does not consume a counter when authentication fails", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn();
    const getSessionContext = jest.fn().mockRejectedValue(new Error("login failed"));

    await expect(
      build(db, postSigned, config(), jest.fn(), getSessionContext).registerInvoiceWithEims(
        INVOICE_ID,
      ),
    ).rejects.toThrow(/login failed/);

    expect(postSigned).not.toHaveBeenCalled();
    expect(db.state).toMatchObject({ nextInvoiceCounter: 7, inFlightInvoiceId: null });
    expect(db.invoices.get(INVOICE_ID)!.eimsStatus).toBe(EimsInvoiceStatus.NotSubmitted);
  });

  it("is idempotent — an invoice with an IRN never reaches EIMS", async () => {
    const db = new FakeDb([
      invoiceRow({ eimsIrn: IRN, eimsStatus: EimsInvoiceStatus.Registered }),
    ]);
    const postSigned = jest.fn();

    const view = await build(db, postSigned).registerInvoiceWithEims(INVOICE_ID);

    expect(postSigned).not.toHaveBeenCalled();
    expect(view.eimsIrn).toBe(IRN);
  });

  it("lets only one of two concurrent calls reach EIMS", async () => {
    const db = new FakeDb([invoiceRow()]);
    let resolvePost: (v: unknown) => void = () => {};
    const postSigned = jest
      .fn()
      .mockImplementation(() => new Promise((resolve) => (resolvePost = resolve)));
    const service = build(db, postSigned);

    const first = service.registerInvoiceWithEims(INVOICE_ID);
    // Let the first reservation commit and its HTTP call start; it is now parked on `resolvePost`.
    await new Promise((resolve) => setImmediate(resolve));
    expect(postSigned).toHaveBeenCalledTimes(1);

    const second = service.registerInvoiceWithEims(INVOICE_ID);

    await expect(second).rejects.toBeInstanceOf(ConflictException);
    resolvePost(okResponse());
    await first;
    expect(postSigned).toHaveBeenCalledTimes(1);
  });

  it("blocks a different invoice while a submission is in flight (survives a restart)", async () => {
    // A committed reservation left behind by a dead process.
    const db = new FakeDb(
      [
        invoiceRow({ eimsStatus: EimsInvoiceStatus.Submitting, eimsInvoiceCounter: 7 }),
        invoiceRow({ id: OTHER_INVOICE_ID, invoiceNumber: "INV-20260807-00043" }),
      ],
      { inFlightInvoiceId: INVOICE_ID, inFlightCounter: 7, nextInvoiceCounter: 8 },
    );
    const postSigned = jest.fn();

    await expect(
      build(db, postSigned).registerInvoiceWithEims(OTHER_INVOICE_ID),
    ).rejects.toThrow(/already in flight/);
    expect(postSigned).not.toHaveBeenCalled();
  });

  it("fails locally on incomplete tax configuration, with zero HTTP calls", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn();

    await expect(
      build(db, postSigned, config({ taxCode: "", taxRatePercent: null })).registerInvoiceWithEims(
        INVOICE_ID,
      ),
    ).rejects.toBeInstanceOf(BadRequestException);

    expect(postSigned).not.toHaveBeenCalled();
    expect(db.invoices.get(INVOICE_ID)!.eimsStatus).toBe(EimsInvoiceStatus.NotSubmitted);
    expect(db.state).toMatchObject({ nextInvoiceCounter: 7, inFlightInvoiceId: null });
  });

  it.each([
    ["SCHEMA_VALIDATION", 400],
    ["RULE_VALIDATION", 406],
  ])("marks %s (%i) FAILED and clears the global block", async (kind, status) => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn().mockRejectedValue(apiError(kind, status));

    await expect(build(db, postSigned).registerInvoiceWithEims(INVOICE_ID)).rejects.toBeInstanceOf(
      EimsApiException,
    );

    expect(db.invoices.get(INVOICE_ID)).toMatchObject({
      eimsStatus: EimsInvoiceStatus.Failed,
      eimsIrn: null,
    });
    expect(db.state).toMatchObject({
      inFlightInvoiceId: null,
      blockedReason: null,
      previousIrn: null,
      // Returned, not consumed: MoR tracks the sequence and rejects a gap
      // ("Invoice counter is not correct. expected : 1").
      nextInvoiceCounter: 7,
    });
  });

  it("treats a success response with no IRN as a failed registration", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn().mockResolvedValue({ statusCode: 200, body: { irn: "" } });

    await expect(build(db, postSigned).registerInvoiceWithEims(INVOICE_ID)).rejects.toThrow(
      /returned no IRN/,
    );
    expect(db.invoices.get(INVOICE_ID)!.eimsStatus).toBe(EimsInvoiceStatus.Failed);
    expect(db.state).toMatchObject({ inFlightInvoiceId: null, blockedReason: null });
  });

  it("marks a timeout UNKNOWN and keeps the system blocked", async () => {
    const db = new FakeDb([invoiceRow()]);
    const postSigned = jest.fn().mockRejectedValue(apiError("TIMEOUT"));

    await expect(build(db, postSigned).registerInvoiceWithEims(INVOICE_ID)).rejects.toBeInstanceOf(
      EimsApiException,
    );

    expect(db.invoices.get(INVOICE_ID)).toMatchObject({
      eimsStatus: EimsInvoiceStatus.Unknown,
      eimsIrn: null,
    });
    expect(db.state!.inFlightInvoiceId).toBe(INVOICE_ID);
    expect(db.state!.blockedReason).toMatch(/never acknowledged/);
    expect(db.state!.previousIrn).toBeNull();
  });

  it("an UNKNOWN result blocks a different invoice too", async () => {
    const db = new FakeDb([invoiceRow(), invoiceRow({ id: OTHER_INVOICE_ID })]);
    const postSigned = jest.fn().mockRejectedValueOnce(apiError("TIMEOUT"));
    const service = build(db, postSigned);

    await expect(service.registerInvoiceWithEims(INVOICE_ID)).rejects.toBeInstanceOf(
      EimsApiException,
    );
    await expect(service.registerInvoiceWithEims(OTHER_INVOICE_ID)).rejects.toThrow(
      /registration is blocked/,
    );
    expect(postSigned).toHaveBeenCalledTimes(1);
  });

  it("returns both the counter and the document number after a refusal, keeps both after an ambiguous result", async () => {
    const db = new FakeDb([invoiceRow(), invoiceRow({ id: OTHER_INVOICE_ID })]);
    const postSigned = jest
      .fn()
      .mockRejectedValueOnce(apiError("RULE_VALIDATION", 406))
      .mockResolvedValueOnce(okResponse());
    const service = build(db, postSigned);

    await expect(service.registerInvoiceWithEims(INVOICE_ID)).rejects.toBeInstanceOf(
      EimsApiException,
    );
    await service.registerInvoiceWithEims(OTHER_INVOICE_ID);

    // A deterministic rejection rolls both numbers back — MoR's expected-next-value for either
    // sequence only advances on acceptance (rule 7001 for DocumentNumber, same as InvoiceCounter).
    const first = postSigned.mock.calls[0][1] as EimsInvoiceRequest;
    const second = postSigned.mock.calls[1][1] as EimsInvoiceRequest;
    expect(first.SourceSystem.InvoiceCounter).toBe(7);
    expect(second.SourceSystem.InvoiceCounter).toBe(7);
    expect(first.DocumentDetails.DocumentNumber).toBe("5");
    expect(second.DocumentDetails.DocumentNumber).toBe("5");
  });

  it("blocks and alerts with the real IRN when MoR accepts but persisting it locally fails", async () => {
    const db = new FakeDb([invoiceRow()]);
    const notify = jest.fn().mockResolvedValue(undefined);
    const postSigned = jest.fn().mockResolvedValue(okResponse());

    // 1st/2nd calls are the reserve() updates; the 3rd is settleSuccess's invoice update — the one
    // that actually failed live (eims_irn too narrow for the real value MoR returned).
    let call = 0;
    const manager = (db as unknown as { manager: { update: jest.Mock } }).manager;
    const realUpdate = manager.update;
    manager.update = jest.fn(async (entity: unknown, id: string, patch: Record<string, unknown>) => {
      call++;
      if (call === 3) throw new Error("value too long for type character varying(64)");
      return realUpdate(entity, id, patch);
    });

    await expect(
      build(db, postSigned, config(), jest.fn(), undefined, notify).registerInvoiceWithEims(
        INVOICE_ID,
      ),
    ).rejects.toThrow(/value too long/);

    // The IRN is never lost, even though the normal success path never committed.
    expect(db.state?.blockedReason).toContain(IRN);
    expect(db.state?.blockedReason).toContain("ACCEPTED");
    expect(db.invoices.get(INVOICE_ID)?.eimsStatus).toBe(EimsInvoiceStatus.Submitting);

    expect(notify).toHaveBeenCalledTimes(1);
    const sent = notify.mock.calls[0][0];
    expect(sent.priority).toBe("HIGH");
    expect(sent.body).toContain(IRN);
  });
});

describe("EimsInvoiceRegistrationService staff alerting", () => {
  it("raises a high-priority alert when a result is ambiguous, because all filing is blocked", async () => {
    const db = new FakeDb([invoiceRow()]);
    const notify = jest.fn().mockResolvedValue(undefined);
    const postSigned = jest.fn().mockRejectedValue(apiError("TIMEOUT"));

    await expect(
      build(db, postSigned, config(), jest.fn(), undefined, notify).registerInvoiceWithEims(
        INVOICE_ID,
      ),
    ).rejects.toBeInstanceOf(EimsApiException);

    expect(notify).toHaveBeenCalledTimes(1);
    const sent = notify.mock.calls[0][0];
    expect(sent.priority).toBe("HIGH");
    expect(sent.title).toMatch(/blocked/i);
    expect(sent.recipients.permissionKeys).toContain("edr_freight_app:invoices:eims_resolve");
  });

  it("raises a normal-priority alert for a deterministic rejection", async () => {
    const db = new FakeDb([invoiceRow()]);
    const notify = jest.fn().mockResolvedValue(undefined);
    const postSigned = jest.fn().mockRejectedValue(apiError("RULE_VALIDATION", 406));

    await expect(
      build(db, postSigned, config(), jest.fn(), undefined, notify).registerInvoiceWithEims(
        INVOICE_ID,
      ),
    ).rejects.toBeInstanceOf(EimsApiException);

    expect(notify.mock.calls[0][0].priority).toBe("NORMAL");
  });

  it("does not alert on a successful filing", async () => {
    const db = new FakeDb([invoiceRow()]);
    const notify = jest.fn();

    await build(db, jest.fn().mockResolvedValue(okResponse()), config(), jest.fn(), undefined, notify)
      .registerInvoiceWithEims(INVOICE_ID);

    expect(notify).not.toHaveBeenCalled();
  });

  it("lets the filing outcome stand even if the alert itself fails", async () => {
    const db = new FakeDb([invoiceRow()]);
    const notify = jest.fn().mockRejectedValue(new Error("inbox down"));
    const postSigned = jest.fn().mockRejectedValue(apiError("RULE_VALIDATION", 406));

    await expect(
      build(db, postSigned, config(), jest.fn(), undefined, notify).registerInvoiceWithEims(
        INVOICE_ID,
      ),
    ).rejects.toThrow(/EIMS register failed \(406\)/);

    expect(db.invoices.get(INVOICE_ID)!.eimsStatus).toBe(EimsInvoiceStatus.Failed);
  });
});

describe("EimsInvoiceRegistrationService.verifyInvoiceWithEims", () => {
  it("verifies the stored IRN over the unsigned bearer transport", async () => {
    const db = new FakeDb([invoiceRow({ eimsIrn: IRN })]);
    const postSigned = jest.fn();
    const postBearer = jest.fn().mockResolvedValue(verifyResponse());

    const result = await build(db, postSigned, config(), postBearer).verifyInvoiceWithEims(
      INVOICE_ID,
    );

    // Lowercase `irn`, raw body — not a signed envelope. `postSigned` must stay untouched.
    expect(postBearer).toHaveBeenCalledWith("/v1/verify", { irn: IRN });
    expect(postSigned).not.toHaveBeenCalled();
    expect(result.body).toMatchObject({ Irn: IRN });
  });

  it("rejects a 200 that carries no Irn", async () => {
    const db = new FakeDb([invoiceRow({ eimsIrn: IRN })]);
    const postBearer = jest.fn().mockResolvedValue({ statusCode: 200, body: { Irn: "  " } });

    await expect(
      build(db, jest.fn(), config(), postBearer).verifyInvoiceWithEims(INVOICE_ID),
    ).rejects.toThrow(/returned no Irn/);
  });

  it("refuses to verify an invoice with no IRN", async () => {
    const db = new FakeDb([invoiceRow({ eimsStatus: EimsInvoiceStatus.Unknown })]);
    const postBearer = jest.fn();

    await expect(
      build(db, jest.fn(), config(), postBearer).verifyInvoiceWithEims(INVOICE_ID),
    ).rejects.toThrow(/no EIMS IRN to verify/);
    expect(postBearer).not.toHaveBeenCalled();
  });
});

describe("EimsInvoiceRegistrationService.resolveEimsRegistration", () => {
  const blocked = () =>
    new FakeDb(
      [
        invoiceRow({
          eimsStatus: EimsInvoiceStatus.Unknown,
          eimsInvoiceCounter: 7,
          eimsDocumentNumber: DOCUMENT_NUMBER,
        }),
      ],
      {
      inFlightInvoiceId: INVOICE_ID,
      inFlightCounter: 7,
      nextInvoiceCounter: 8,
      blockedReason: "never acknowledged",
    });

  it("records a confirmed IRN, resumes the chain and clears the block", async () => {
    const db = blocked();
    const postBearer = jest.fn().mockResolvedValue(verifyResponse());

    const view = await build(db, jest.fn(), config(), postBearer).resolveEimsRegistration(
      INVOICE_ID,
      { irn: IRN },
    );

    // The IRN is confirmed at the gateway before it is ever written.
    expect(postBearer).toHaveBeenCalledWith("/v1/verify", { irn: IRN });
    expect(view).toMatchObject({ eimsStatus: EimsInvoiceStatus.Registered, eimsIrn: IRN });
    expect(db.state).toMatchObject({
      previousIrn: IRN,
      inFlightInvoiceId: null,
      blockedReason: null,
    });
  });

  it("refuses an IRN the gateway answers with a different one, leaving the block intact", async () => {
    const db = blocked();
    const postBearer = jest
      .fn()
      .mockResolvedValue(verifyResponse({ Irn: "0000000000000000000000000000000000000000" }));

    await expect(
      build(db, jest.fn(), config(), postBearer).resolveEimsRegistration(INVOICE_ID, { irn: IRN }),
    ).rejects.toThrow(/answered the lookup for IRN/);

    expect(db.invoices.get(INVOICE_ID)).toMatchObject({
      eimsStatus: EimsInvoiceStatus.Unknown,
      eimsIrn: null,
    });
    expect(db.state).toMatchObject({
      inFlightInvoiceId: INVOICE_ID,
      blockedReason: "never acknowledged",
      previousIrn: null,
    });
  });

  it("refuses an IRN whose document number is not this invoice, leaving the block intact", async () => {
    const db = blocked();
    const postBearer = jest.fn().mockResolvedValue(
      verifyResponse({
        DocumentDetails: { Type: "INV", DocumentNumber: "99999" },
      }),
    );

    await expect(
      build(db, jest.fn(), config(), postBearer).resolveEimsRegistration(INVOICE_ID, { irn: IRN }),
    ).rejects.toThrow(/not 5/);

    expect(db.invoices.get(INVOICE_ID)).toMatchObject({
      eimsStatus: EimsInvoiceStatus.Unknown,
      eimsIrn: null,
    });
    expect(db.state).toMatchObject({
      inFlightInvoiceId: INVOICE_ID,
      blockedReason: "never acknowledged",
      previousIrn: null,
    });
  });

  it("refuses an IRN the gateway does not acknowledge at all", async () => {
    const db = blocked();
    const postBearer = jest.fn().mockResolvedValue({ statusCode: 200, body: {} });

    await expect(
      build(db, jest.fn(), config(), postBearer).resolveEimsRegistration(INVOICE_ID, { irn: IRN }),
    ).rejects.toThrow(/returned no Irn/);
    expect(db.state!.blockedReason).toBe("never acknowledged");
  });

  it("discards the attempt, leaving the chain where it was", async () => {
    const db = blocked();
    const postBearer = jest.fn();

    const view = await build(db, jest.fn(), config(), postBearer).resolveEimsRegistration(
      INVOICE_ID,
      { discard: true },
    );

    expect(view).toMatchObject({ eimsStatus: EimsInvoiceStatus.Failed, eimsIrn: null });
    expect(postBearer).not.toHaveBeenCalled(); // nothing to confirm
    expect(db.state).toMatchObject({
      previousIrn: null,
      inFlightInvoiceId: null,
      blockedReason: null,
    });
  });

  it("refuses to resolve an invoice that is not the in-flight one", async () => {
    const db = blocked();
    db.invoices.set(
      OTHER_INVOICE_ID,
      invoiceRow({ id: OTHER_INVOICE_ID, eimsDocumentNumber: "6" }),
    );
    const postBearer = jest.fn().mockResolvedValue(verifyResponse());

    await expect(
      build(db, jest.fn(), config(), postBearer).resolveEimsRegistration(OTHER_INVOICE_ID, {
        irn: IRN,
      }),
    ).rejects.toThrow(/in-flight EIMS submission is invoice/);
  });

  it("requires either an IRN or an explicit discard", async () => {
    await expect(
      build(blocked(), jest.fn()).resolveEimsRegistration(INVOICE_ID, {}),
    ).rejects.toBeInstanceOf(BadRequestException);
  });
});