15_getTheTitles : Added more tests

[maitreverge]

Because

Despite the README.md mentionning the mandatory use of a a built-in javascript method, we can still pass this exercice with a simple solution including a bracket notation like:

const getTheTitles = function(arr) {
	let result = []
	
	result.push(arr[0]["title"]);
	result.push(arr[1]["title"]);
	return result;
};

// Do not edit below this line
module.exports = getTheTitles;

I added more tests to avoid this simple solution.

This PR

• The file getTheTitles.spec.js and getTheTitles-solution.spec.js has been changed.
• The following variables has been added...

  // An array dynamically generated
  const largeBooks = Array.from({ length: 1000 }, (_, i) => ({
    title: `Title${i}`,
    author: `Author${i}`,
  }));

  // And an array with different values types as book title.
  const booksWithNonStringTitles = [
    {
		title: 123,
		author: 'A',
	},
    {
		title: null,
		author: 'B',
	},
    {
		title: 'Valid',
		author: 'C',
	},
  ];

• ...and their related test

  test.skip('returns empty array for empty input', () => {
    expect(getTheTitles([])).toEqual([]);
  });
  test.skip('handles large array', () => {
    expect(getTheTitles(largeBooks)).toEqual(largeBooks.map((b) => b.title));
  });
  test.skip('handles non-string titles', () => {
    expect(getTheTitles(booksWithNonStringTitles)).toEqual([
      123,
      null,
      'Valid',
    ]);
  });

Pull Request Requirements

• [ x ] I have thoroughly read and understand The Odin Project Contributing Guide
• [ x ] The title of this PR follows the location of change: brief description of change format, e.g. 01_helloWorld: Update test cases
• [ x ] The Because section summarizes the reason for this PR
• [ x ] The This PR section has a bullet point list describing the changes in this PR
• [ ] If this PR addresses an open issue, it is linked in the Issue section
• [ x ] If this PR includes any changes that affect the solution of an exercise, I've also updated the solution in the /solutions folder

[mao-sz]

Thanks @maitreverge

I'm on board with the booksWithNonStringTitles extra case, mainly because it has a different length.
I'd like the largeBooks array and test case removed though, because it actually leaks a solution in the test assertion :P

Technically, if someone loops over the array and .pushes to a new array, they're using a built-in JS method so that's perfectly acceptable, and the exercise is not trying to enforce the use of .map only.