export default function createLruCache(maxSize) {
  throw new Error('Not implemented');
}

import createLruCache from './createLruCache';

describe('createLruCache', () => {
  test('throws for invalid maxSize', () => {
    expect(() => createLruCache(0)).toThrow();
    expect(() => createLruCache(-1)).toThrow();
    expect(() => createLruCache(1.5)).toThrow();
  });

  test('evicts least-recently-used on overflow', () => {
    const c = createLruCache(2);
    c.set('a', 1);
    c.set('b', 2);
    c.set('c', 3);

    expect(c.has('a')).toBe(false);
    expect(c.has('b')).toBe(true);
    expect(c.has('c')).toBe(true);
    expect(c.keys()).toEqual(['b', 'c']);
  });

  test('get refreshes recency', () => {
    const c = createLruCache(2);
    c.set('a', 1);
    c.set('b', 2);

    expect(c.get('a')).toBe(1);
    c.set('c', 3);

    expect(c.has('b')).toBe(false);
    expect(c.keys()).toEqual(['a', 'c']);
  });

  test('updating an existing key does not grow size', () => {
    const c = createLruCache(2);
    c.set('a', 1);
    c.set('b', 2);
    c.set('a', 10);

    expect(c.size()).toBe(2);
    expect(c.get('a')).toBe(10);
  });
});