import { expect, test } from "vitest";
import LRUCache from "./LRUCache";

test("LRUCache", () => {
  const cache = new LRUCache<number>(20);
  // Add more items than is the capacity.
  for (let i = 0; i < 25; i += 1) {
    cache.set(i.toString(), i);
  }
  // Check that oldest items were removed from the cache.
  for (let i = 0; i < 5; i += 1) {
    expect(cache.get(i.toString())).toEqual(null);
  }
  // Check that newest items remained.
  for (let i = 24; i >= 5; i -= 1) {
    expect(cache.get(i.toString())).toEqual(i);
  }
  // Check that get counts towards usage.
  // 24 should be the least recently used number at this point.
  cache.set("25", 25);
  expect(cache.get("24")).toEqual(null);
  expect(cache.get("23")).toEqual(23);

  // Check that purge works
  cache.purge();
  for (let i = 0; i <= 25; i += 1) {
    expect(cache.get(i.toString())).toEqual(null);
  }
});