import Decimal, { DecimalSource, format } from "util/bignum"; import { expect } from "vitest"; interface CustomMatchers { compare_tolerance(expected: DecimalSource, tolerance?: number): R; } declare global { // eslint-disable-next-line @typescript-eslint/no-namespace namespace Vi { // 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) }; } });