Tender Path Obligations

A COMPLETENESS ORACLE that proves EVERY WAY OF PAYING for an order records THE SAME SET OF OBLIGATIONS -- or names exactly which one is missing, wrong, or never checked.

THE SILENT FAILURE. An order can be settled several ways: a card charge, store credit, a comp, a refund reversal. Each path is written at a different time by a different person for a different reason, and each is supposed to record the same consequences -- the revenue line, the tax liability, the loyalty accrual, the inventory movement, the payout owed to a seller.

One of them records one fewer. Nothing errors, because each path is internally consistent and every individual order balances. The discrepancy only exists ACROSS paths, and only in aggregate, which is why it is found at month end by someone reconciling a total that is wrong by an amount nobody can attribute.

TESTING EACH PATH SEPARATELY CANNOT FIND THIS. Every path passes its own tests, because every path does what its author intended. The bug is in the SET -- an obligation that exists in three paths and not the fourth -- and no test that looks at one path at a time is looking at the set.

So this treats the obligations as the specification and the paths as candidate implementations of it, reporting the exact obligation-by-path matrix and where the holes are. It also flags obligations no path records at all, which is the case nobody writes a test for because nobody remembered it.

VERIFIED: 55 tests, measured by running the suite.

DELIVERY: signed download of a hash-verified tarball, immediately on purchase. Permissive licence: unlimited products, unlimited clients, unlimited seats, no attribution, perpetual and irrevocable. One restriction, do not republish the source as source.

Interface

What you call, and what comes back. Types and signatures only — the implementation ships with the source.

  export function money(amountMinorUnits: number, currency: string): Money;
  export function moneyEquals(a: Money, b: Money): boolean;
  export function moneyObligation(amount: Money, payee?: string): ObligationValue;
  export function markerObligation(detail: string): ObligationValue;
  export function recorded(value: ObligationValue): ObligationRecord;
  export function exempt(reason: string): ObligationRecord;
  export function evaluateCompleteness(sale: SaleDeclaration): CompletenessReport;
  export function evaluatePath( obligations: readonly ObligationSpecEntry[], path: TenderPathInput, ): PathReport;
  export function allPathsComplete(report: CompletenessReport): boolean;
  export function verdictFor(report: CompletenessReport, pathId: string): PathVerdict | undefined;
  export function summarizeReport(report: CompletenessReport): string;

  export type ObligationValue = | { readonly kind: "money";
  export type ObligationRecord = | { readonly status: "recorded";
  export type PathVerdict = "COMPLETE" | "INCOMPLETE" | "UNPROVEN";
  export type FindingStatus = "matched" | "divergent" | "missing" | "exempt" | "unproven";