Method _checkFakeTimers

packages/jest-fake-timers/src/legacyFakeTimers.ts:423–438

()

  }

  private _checkFakeTimers() {
    if (!this._fakingTime) {
      this._global.console.warn(
        'A function to advance timers was called but the timers APIs are not mocked ' +
          'with fake timers. Call `jest.useFakeTimers({legacyFakeTimers: true})` ' +
          'in this test file or enable fake timers for all tests by setting ' +
          "{'enableGlobally': true, 'legacyFakeTimers': true} in " +
          `Jest configuration file.\nStack Trace:\n${formatStackTrace(
            // eslint-disable-next-line unicorn/error-message
            new Error().stack!,
            this._config,
            {noStackTrace: false},
          )}`,
      );
    }
  }

  #createMockFunction<T extends FunctionLike = UnknownFunction>(
    implementation: T,