wehub-resource-sync
120 lines
3.6 KiB
JavaScript
120 lines
3.6 KiB
JavaScript
import { LRUCache } from "../../src/utils/lru_cache.js";
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describe("LRUCache", () => {
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it("should return undefined for non-existent keys", () => {
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const cache = new LRUCache(2);
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expect(cache.get("nonexistent")).toEqual(undefined);
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});
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it("should store and retrieve values correctly", () => {
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const cache = new LRUCache(2);
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cache.put("a", 1);
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cache.put("b", 2);
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expect(cache.get("a")).toEqual(1);
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expect(cache.get("b")).toEqual(2);
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});
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it("should update the value and refresh the usage", () => {
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const cache = new LRUCache(2);
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cache.put("a", 1);
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cache.put("b", 2);
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// Update key "a"
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cache.put("a", 10);
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expect(cache.get("a")).toEqual(10);
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// Access "a" so "b" becomes the LRU
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cache.get("a");
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cache.put("c", 3);
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// "b" should be evicted since it is the least recently used.
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expect(cache.get("b")).toEqual(undefined);
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expect(cache.get("c")).toEqual(3);
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});
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it("should evict the least recently used item when capacity is exceeded", () => {
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const cache = new LRUCache(3);
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cache.put("a", 1);
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cache.put("b", 2);
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cache.put("c", 3);
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// Access "a" to refresh its recentness.
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cache.get("a");
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// Insert a new key, this should evict "b" as it is the least recently used.
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cache.put("d", 4);
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expect(cache.get("b")).toEqual(undefined);
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expect(cache.get("a")).toEqual(1);
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expect(cache.get("c")).toEqual(3);
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expect(cache.get("d")).toEqual(4);
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});
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it("should update the usage order on get", () => {
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const cache = new LRUCache(3);
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cache.put("a", "apple");
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cache.put("b", "banana");
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cache.put("c", "cherry");
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// Access "a" making it most recently used.
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expect(cache.get("a")).toEqual("apple");
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// Insert new element to evict the least recently used ("b").
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cache.put("d", "date");
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expect(cache.get("b")).toEqual(undefined);
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// "a", "c", and "d" should be present.
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expect(cache.get("a")).toEqual("apple");
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expect(cache.get("c")).toEqual("cherry");
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expect(cache.get("d")).toEqual("date");
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});
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it("should clear the cache", () => {
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const cache = new LRUCache(2);
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cache.put("a", 1);
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cache.put("b", 2);
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cache.clear();
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expect(cache.get("a")).toEqual(undefined);
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expect(cache.get("b")).toEqual(undefined);
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});
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it("should return true when deleting an existing key", () => {
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const cache = new LRUCache(2);
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cache.put("a", 1);
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expect(cache.delete("a")).toEqual(true);
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});
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it("should return false when deleting a non-existent key", () => {
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const cache = new LRUCache(2);
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expect(cache.delete("nonexistent")).toEqual(false);
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});
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it("should make a deleted key unretrievable", () => {
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const cache = new LRUCache(2);
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cache.put("a", 1);
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cache.delete("a");
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expect(cache.get("a")).toEqual(undefined);
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});
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it("should allow re-inserting a deleted key", () => {
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const cache = new LRUCache(2);
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cache.put("a", 1);
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cache.delete("a");
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cache.put("a", 2);
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expect(cache.get("a")).toEqual(2);
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});
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it("should not affect other entries when deleting a key", () => {
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const cache = new LRUCache(3);
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cache.put("a", 1);
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cache.put("b", 2);
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cache.put("c", 3);
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cache.delete("b");
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expect(cache.get("a")).toEqual(1);
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expect(cache.get("b")).toEqual(undefined);
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expect(cache.get("c")).toEqual(3);
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});
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it("should free up space after deletion, preventing unwanted eviction", () => {
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const cache = new LRUCache(2);
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cache.put("a", 1);
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cache.put("b", 2);
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cache.delete("a");
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// With "a" deleted, inserting "c" should not evict "b"
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cache.put("c", 3);
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expect(cache.get("b")).toEqual(2);
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expect(cache.get("c")).toEqual(3);
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});
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});
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