import Decimal, { DecimalSource, format } from "util/bignum"; import { Mock, expect, vi } from "vitest"; interface CustomMatchers { compare_tolerance(expected: DecimalSource, tolerance?: number): R; toLogError(): R; } declare module "vitest" { // eslint-disable-next-line @typescript-eslint/no-empty-interface interface Assertion extends CustomMatchers {} // eslint-disable-next-line @typescript-eslint/no-empty-interface interface AsymmetricMatchersContaining extends CustomMatchers {} } expect.extend({ compare_tolerance(received: DecimalSource, expected: DecimalSource, tolerance?: number) { const { isNot } = this; let pass = false; if (!Decimal.isFinite(expected)) { pass = !Decimal.isFinite(received); } else if (Decimal.isNaN(expected)) { pass = Decimal.isNaN(received); } else { pass = Decimal.eq_tolerance(received, expected, tolerance); } return { // do not alter your "pass" based on isNot. Vitest does it for you pass, message: () => `Expected ${received} to${ (isNot as boolean) ? " not" : "" } be close to ${expected}`, expected: format(expected), actual: format(received) }; }, toLogError(received: () => unknown) { const { isNot } = this; console.error = vi.fn(); received(); const calls = ( console.error as Mock< Parameters, ReturnType > ).mock.calls.length; const pass = calls >= 1; vi.restoreAllMocks(); return { pass, message: () => `Expected ${received} to ${(isNot as boolean) ? " not" : ""} log an error`, expected: "1+", actual: calls }; } });