simple-tester.js

function describe(description, callback) {
  console.log(description);
  callback();
}

function it(description, callback) {
  console.log(description);
  callback();
}

function expect(left) {
  return {
    toBe(right) {
      if (left !== right) {
        console.log(`    expected "${left}" to be "${right}"`);
      }
    },
  };
}