diff --git a/apps/edr-freight-api/src/modules/reports/definitions/receivables-payables.report.spec.ts b/apps/edr-freight-api/src/modules/reports/definitions/receivables-payables.report.spec.ts
new file mode 100644
index 000000000..76edd2238
--- /dev/null
+++ b/apps/edr-freight-api/src/modules/reports/definitions/receivables-payables.report.spec.ts
@@ -0,0 +1,71 @@
+import { WAGON_CANCELLATION_STATUSES } from '../../bookings/entities/booking-wagon-cancellation.entity';
+import { ShippingLineCreditStatus } from '../../shipping-lines/entities/shipping-line-credit.entity';
+import {
+  CREDIT_LIABILITY_STATUS,
+  INVOICE_SIDE_EXPR,
+  LEDGER_SIDES,
+  UNINVOICED_CREDIT_STATUS,
+  receivablesPayablesReport,
+} from './receivables-payables.report';
+
+/**
+ * The report's whole point is the sign of the money: a cancellation FEE is
+ * owed TO EDR, and the cancelled freight is owed BACK to the customer as
+ * bookable credit. These tests pin the two down at the string level — the SQL
+ * itself is validated against the database, not here.
+ */
+describe('receivables-payables report', () => {
+  it('treats exactly one wagon-cancellation status as a liability', () => {
+    expect(WAGON_CANCELLATION_STATUSES).toContain(CREDIT_LIABILITY_STATUS);
+    // Every other status owes nothing: nothing cut yet (FEE_PENDING), redeemed
+    // (REBOOKED), or voided (WITHDRAWN / EXPIRED). If a new status appears,
+    // this fails until someone decides which side of the ledger it lands on.
+    expect(WAGON_CANCELLATION_STATUSES.filter((s) => s !== CREDIT_LIABILITY_STATUS).sort()).toEqual(
+      ['EXPIRED', 'FEE_PENDING', 'REBOOKED', 'WITHDRAWN'],
+    );
+  });
+
+  it('counts only the shipping-line credit status that has no invoice behind it', () => {
+    expect(UNINVOICED_CREDIT_STATUS).toBe(ShippingLineCreditStatus.Unbilled);
+    // BILLED is debt too, but it is counted through its invoice on the invoice
+    // branch — taking it here as well would double it.
+    expect(UNINVOICED_CREDIT_STATUS).not.toBe(ShippingLineCreditStatus.Billed);
+  });
+
+  it('never classifies the cancellation fee as a payable', () => {
+    // The fee invoice rides the booking's invoice list; while it is open it is
+    // an ordinary receivable balance, and it must not reach a PAYABLE arm.
+    expect(INVOICE_SIDE_EXPR).not.toContain('WAGON_CANCEL_FEE');
+    expect(INVOICE_SIDE_EXPR).not.toContain('CANCELLATION_FEE');
+  });
+
+  it('does not double-count a booking already carried by the cancellation ledger', () => {
+    expect(INVOICE_SIDE_EXPR).toContain('NOT EXISTS');
+    expect(INVOICE_SIDE_EXPR).toContain('booking_wagon_cancellations');
+  });
+
+  it('emits exactly the side keys the filter offers', () => {
+    const declared = LEDGER_SIDES.map((s) => s.value).sort();
+    expect(declared).toEqual([
+      'PAYABLE_PREPAID',
+      'PAYABLE_WAGON_CREDIT',
+      'RECEIVABLE_OPEN',
+      'RECEIVABLE_SL_INVOICED',
+      'RECEIVABLE_SL_UNBILLED',
+    ]);
+    // The summary KPIs split on these prefixes; a key matching neither would
+    // silently vanish from both totals.
+    for (const key of declared) {
+      expect(key.startsWith('RECEIVABLE') || key.startsWith('PAYABLE')).toBe(true);
+    }
+  });
+
+  it('sorts on the union wrapper, never on a branch-local alias', () => {
+    // The runner appends ORDER BY outside the union subquery, where `i.*`,
+    // `b.*` and `bwc.*` do not exist.
+    for (const col of receivablesPayablesReport.columns) {
+      if (!col.sortExpr) continue;
+      expect(col.sortExpr).toMatch(/^r\./);
+    }
+  });
+});