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

import { assertEimsInvoiceConfig, buildEimsContext } from "./eims-invoice-context";
import { eimsConfig } from "./eims-test-fixtures";

const SESSION = { systemNumber: "B0360154BA", systemType: "SYS" };

describe("assertEimsInvoiceConfig — charge-type overrides", () => {
  it("passes when EIMS_TAX_CODE_BY_CHARGE_TYPE and _RATE_ list the same charge types", () => {
    expect(() =>
      assertEimsInvoiceConfig(
        eimsConfig({
          invoice: {
            ...eimsConfig().invoice,
            taxCodeByChargeType: { RAIL_FREIGHT: "VAT0" },
            taxRateByChargeType: { RAIL_FREIGHT: "0" },
          },
        }),
      ),
    ).not.toThrow();
  });

  it("throws when a charge type has a code but no rate, or a rate but no code", () => {
    expect(() =>
      assertEimsInvoiceConfig(
        eimsConfig({
          invoice: {
            ...eimsConfig().invoice,
            taxCodeByChargeType: { RAIL_FREIGHT: "VAT0" },
            taxRateByChargeType: {},
          },
        }),
      ),
    ).toThrow(/mismatched: RAIL_FREIGHT/);

    expect(() =>
      assertEimsInvoiceConfig(
        eimsConfig({
          invoice: {
            ...eimsConfig().invoice,
            taxCodeByChargeType: {},
            taxRateByChargeType: { RAIL_FREIGHT: "0" },
          },
        }),
      ),
    ).toThrow(/mismatched: RAIL_FREIGHT/);
  });

  it("throws when a rate/excise/discount override is not a number", () => {
    expect(() =>
      assertEimsInvoiceConfig(
        eimsConfig({
          invoice: {
            ...eimsConfig().invoice,
            taxCodeByChargeType: { RAIL_FREIGHT: "VAT0" },
            taxRateByChargeType: { RAIL_FREIGHT: "not-a-number" },
          },
        }),
      ),
    ).toThrow(/EIMS_TAX_RATE_BY_CHARGE_TYPE\[RAIL_FREIGHT\]/);

    expect(() =>
      assertEimsInvoiceConfig(
        eimsConfig({ invoice: { ...eimsConfig().invoice, discountByChargeType: { X: "abc" } } }),
      ),
    ).toThrow(/EIMS_DISCOUNT_BY_CHARGE_TYPE\[X\]/);
  });
});

describe("buildEimsContext — taxForLine", () => {
  const input = { documentNumber: "24", invoiceCounter: 7, previousIrn: "", session: SESSION };
  const line = (chargeType: string) => ({ chargeType, quantity: 1, unitRate: 100, amount: 100 });

  it("uses the per-chargeType override when one is configured", () => {
    const context = buildEimsContext(
      eimsConfig({
        invoice: {
          ...eimsConfig().invoice,
          taxCode: "VAT15",
          taxRatePercent: 15,
          taxCodeByChargeType: { RAIL_FREIGHT: "VAT0" },
          taxRateByChargeType: { RAIL_FREIGHT: "0" },
          exciseByChargeType: { RAIL_FREIGHT: "5" },
          discountByChargeType: { RAIL_FREIGHT: "10" },
        },
      }),
      input,
    );

    expect(context.taxForLine(line("RAIL_FREIGHT"), 1)).toEqual({
      code: "VAT0",
      ratePercent: 0,
      exciseTaxValue: 5,
      discount: 10,
    });
  });

  it("falls back to the invoice-wide default for a charge type with no override", () => {
    const context = buildEimsContext(
      eimsConfig({
        invoice: {
          ...eimsConfig().invoice,
          taxCode: "VAT15",
          taxRatePercent: 15,
          exciseTaxValue: 0,
          taxCodeByChargeType: { RAIL_FREIGHT: "VAT0" },
          taxRateByChargeType: { RAIL_FREIGHT: "0" },
        },
      }),
      input,
    );

    expect(context.taxForLine(line("HANDLING"), 1)).toEqual({
      code: "VAT15",
      ratePercent: 15,
      exciseTaxValue: 0,
      discount: 0,
    });
  });
});