verdaccio/test/e2e-cli/utils/expect.ts

import * as fs from 'fs-extra';

export function expectFileToExist(fileName: string) {
  return new Promise((resolve, reject) => {
    fs.exists(fileName, (exist) => {
      if (exist) {
        resolve(exist);
      } else {
        reject(new Error(`File ${fileName} was expected to exist but not found...`));
      }
    });
  });
}