/**
* Tests for smart sign detection algorithm
*/
import { describe, expect, it } from "vitest";
import type {
BankTransaction,
NormalizedYNABTransaction,
} from "../../../types/reconciliation.js";
import { detectSignInversion } from "../signDetector.js";
describe("detectSignInversion", () => {
it("detects when bank amounts need inversion (opposite signs)", () => {
// Bank CSV shows charges as POSITIVE (banking convention)
const bankTransactions: BankTransaction[] = [
{ id: "1", date: "2025-11-20", amount: 10000, payee: "Grocery Store" }, // +$10
{ id: "2", date: "2025-11-21", amount: 5000, payee: "Gas Station" }, // +$5
{ id: "3", date: "2025-11-22", amount: 20000, payee: "Restaurant" }, // +$20
];
// YNAB shows charges as NEGATIVE
const ynabTransactions: NormalizedYNABTransaction[] = [
{
id: "y1",
date: "2025-11-20",
amount: -10000, // -$10
payee: "Grocery Store",
cleared: "uncleared",
approved: true,
deleted: false,
},
{
id: "y2",
date: "2025-11-21",
amount: -5000, // -$5
payee: "Gas Station",
cleared: "uncleared",
approved: true,
deleted: false,
},
{
id: "y3",
date: "2025-11-22",
amount: -20000, // -$20
payee: "Restaurant",
cleared: "uncleared",
approved: true,
deleted: false,
},
];
const result = detectSignInversion(bankTransactions, ynabTransactions);
expect(result).toBe(true); // Need inversion
});
it("detects when bank amounts do NOT need inversion (same signs)", () => {
// Bank CSV already uses YNAB convention (Wealthsimple case)
const bankTransactions: BankTransaction[] = [
{ id: "1", date: "2025-11-20", amount: -10000, payee: "Grocery Store" }, // -$10
{ id: "2", date: "2025-11-21", amount: -5000, payee: "Gas Station" }, // -$5
{ id: "3", date: "2025-11-22", amount: -20000, payee: "Restaurant" }, // -$20
];
// YNAB also shows charges as NEGATIVE
const ynabTransactions: NormalizedYNABTransaction[] = [
{
id: "y1",
date: "2025-11-20",
amount: -10000,
payee: "Grocery Store",
cleared: "uncleared",
approved: true,
deleted: false,
},
{
id: "y2",
date: "2025-11-21",
amount: -5000,
payee: "Gas Station",
cleared: "uncleared",
approved: true,
deleted: false,
},
{
id: "y3",
date: "2025-11-22",
amount: -20000,
payee: "Restaurant",
cleared: "uncleared",
approved: true,
deleted: false,
},
];
const result = detectSignInversion(bankTransactions, ynabTransactions);
expect(result).toBe(false); // No inversion needed
});
it("handles mixed positive and negative amounts correctly", () => {
// Bank CSV with charges (positive) and payment (negative)
const bankTransactions: BankTransaction[] = [
{ id: "1", date: "2025-11-20", amount: 10000, payee: "Purchase" },
{ id: "2", date: "2025-11-21", amount: -20000, payee: "Payment" }, // Credit
{ id: "3", date: "2025-11-22", amount: 5000, payee: "Purchase" },
];
// YNAB with charges (negative) and payment (positive)
const ynabTransactions: NormalizedYNABTransaction[] = [
{
id: "y1",
date: "2025-11-20",
amount: -10000,
payee: "Purchase",
cleared: "uncleared",
approved: true,
deleted: false,
},
{
id: "y2",
date: "2025-11-21",
amount: 20000, // Payment (positive in YNAB)
payee: "Payment",
cleared: "uncleared",
approved: true,
deleted: false,
},
{
id: "y3",
date: "2025-11-22",
amount: -5000,
payee: "Purchase",
cleared: "uncleared",
approved: true,
deleted: false,
},
];
const result = detectSignInversion(bankTransactions, ynabTransactions);
expect(result).toBe(true); // Need inversion (opposite signs)
});
it("works with small sample sizes", () => {
const bankTransactions: BankTransaction[] = [
{ id: "1", date: "2025-11-20", amount: 10000, payee: "Store" },
];
const ynabTransactions: NormalizedYNABTransaction[] = [
{
id: "y1",
date: "2025-11-20",
amount: -10000,
payee: "Store",
cleared: "uncleared",
approved: true,
deleted: false,
},
];
const result = detectSignInversion(bankTransactions, ynabTransactions);
expect(result).toBe(true);
});
it("returns false when no matching transactions found", () => {
const bankTransactions: BankTransaction[] = [
{ id: "1", date: "2025-11-20", amount: 10000, payee: "Store A" },
];
const ynabTransactions: NormalizedYNABTransaction[] = [
{
id: "y1",
date: "2025-10-20", // Different month
amount: -50000, // Different amount
payee: "Store B",
cleared: "uncleared",
approved: true,
deleted: false,
},
];
const result = detectSignInversion(bankTransactions, ynabTransactions);
// Insufficient evidence: return null when no matches found
expect(result).toBeNull();
});
it("handles empty transaction lists", () => {
const result1 = detectSignInversion([], []);
expect(result1).toBeNull();
const bankTransactions: BankTransaction[] = [
{ id: "1", date: "2025-11-20", amount: 10000, payee: "Store" },
];
const result2 = detectSignInversion(bankTransactions, []);
expect(result2).toBeNull();
const ynabTransactions: NormalizedYNABTransaction[] = [
{
id: "y1",
date: "2025-11-20",
amount: -10000,
payee: "Store",
cleared: "uncleared",
approved: true,
deleted: false,
},
];
const result3 = detectSignInversion([], ynabTransactions);
expect(result3).toBeNull();
});
});
