Enhanced

const { addScore, getLeaderboard, resetLeaderboard } = require('./leaderboard');

describe('Leaderboard Functions', () => {
  beforeEach(() => {
    resetLeaderboard(); // Reset the leaderboard before each test
  });

  test('should add a score correctly', () => {
    addScore('Alice', 100);
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([{ name: 'Alice', score: 100 }]);
  });

  test('should update score for existing user', () => {
    addScore('Bob', 50);
    addScore('Bob', 75); // Update score
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([{ name: 'Bob', score: 75 }]);
  });

  test('should return an empty leaderboard if no scores added', () => {
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([]);
  });

  test('should handle multiple users correctly', () => {
    addScore('Alice', 100);
    addScore('Bob', 200);
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([
      { name: 'Alice', score: 100 },
      { name: 'Bob', score: 200 },
    ]);
  });

  test('should maintain leaderboard order if sorted by score', () => {
    addScore('Charlie', 150);
    addScore('Alice', 100);
    addScore('Bob', 200);
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([
      { name: 'Bob', score: 200 },
      { name: 'Charlie', score: 150 },
      { name: 'Alice', score: 100 },
    ]);
  });

  test('should reset the leaderboard correctly', () => {
    addScore('Alice', 100);
    resetLeaderboard();
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([]);
  });

  test('should handle zero and negative scores', () => {
    addScore('NegativeUser', -50);
    addScore('ZeroUser', 0);
    const leaderboard = getLeaderboard();
    expect(leaderboard).toContainEqual({ name: 'NegativeUser', score: -50 });
    expect(leaderboard).toContainEqual({ name: 'ZeroUser', score: 0 });
  });

  test('should handle large scores correctly', () => {
    addScore('BigScoreUser', 1000000);
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([{ name: 'BigScoreUser', score: 1000000 }]);
  });

  test('should only store the latest score for each user', () => {
    addScore('Alice', 50);
    addScore('Alice', 150);
    const leaderboard = getLeaderboard();
    expect(leaderboard).toEqual([{ name: 'Alice', score: 150 }]);
  });
});