test("declares messageFunc and returns correct message", () => {
  expect(typeof messageFunc).toBe("function");
  expect(messageFunc())
    .toBe("This is a message from the function");
});

test("uses return statement", () => {
  const code = messageFunc.toString();
  expect(code.includes("return")).toBe(true);
});


user_code.test.js

Dive into the world of the most popular language for front-end development – JavaScript. JavaScript is a language built into almost every browser and can be used for a wide variety of tasks. Learn the basic functionality and prepare yourself for the challenges and more advanced programming techniques.

An introduction to JavaScript, covering the basic syntax of the language along with key terms and concepts that form the foundation for learning advanced features. The section includes hands-on tasks designed to help practice these concepts and make the content easy to remember without effort.

Challenge: Simple Function

解答