CookieBridge/projects/cookiebridge/tests/conflict.test.ts

import { describe, it, expect } from "vitest";
import { CookieStore } from "../src/sync/conflict.js";
import type { CookieEntry, CookieSyncPayload } from "../src/protocol/spec.js";

function makeCookie(overrides: Partial<CookieEntry> = {}): CookieEntry {
  return {
    domain: "example.com",
    name: "session",
    value: "abc123",
    path: "/",
    secure: true,
    httpOnly: true,
    sameSite: "lax",
    expiresAt: null,
    ...overrides,
  };
}

describe("CookieStore — conflict resolution", () => {
  it("applies first write", () => {
    const store = new CookieStore();
    const payload: CookieSyncPayload = {
      action: "set",
      cookies: [makeCookie({ value: "v1" })],
      lamportTs: 1,
    };
    const applied = store.applyRemote(payload, "device-a");
    expect(applied).toHaveLength(1);
    expect(store.getAll()).toHaveLength(1);
    expect(store.getAll()[0].value).toBe("v1");
  });

  it("last-writer-wins: higher timestamp wins", () => {
    const store = new CookieStore();
    store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "old" })], lamportTs: 1 },
      "device-a",
    );
    store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "new" })], lamportTs: 5 },
      "device-b",
    );
    expect(store.getAll()[0].value).toBe("new");
  });

  it("rejects stale update", () => {
    const store = new CookieStore();
    store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "newer" })], lamportTs: 10 },
      "device-a",
    );
    const applied = store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "older" })], lamportTs: 3 },
      "device-b",
    );
    expect(applied).toHaveLength(0);
    expect(store.getAll()[0].value).toBe("newer");
  });

  it("breaks ties by deviceId (lexicographic)", () => {
    const store = new CookieStore();
    store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "from-a" })], lamportTs: 5 },
      "aaa",
    );
    // Same timestamp, higher deviceId wins
    const applied = store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "from-b" })], lamportTs: 5 },
      "bbb",
    );
    expect(applied).toHaveLength(1);
    expect(store.getAll()[0].value).toBe("from-b");
  });

  it("tie-break: lower deviceId loses", () => {
    const store = new CookieStore();
    store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "from-z" })], lamportTs: 5 },
      "zzz",
    );
    const applied = store.applyRemote(
      { action: "set", cookies: [makeCookie({ value: "from-a" })], lamportTs: 5 },
      "aaa",
    );
    expect(applied).toHaveLength(0);
    expect(store.getAll()[0].value).toBe("from-z");
  });

  it("handles delete action", () => {
    const store = new CookieStore();
    store.applyRemote(
      { action: "set", cookies: [makeCookie()], lamportTs: 1 },
      "device-a",
    );
    expect(store.getAll()).toHaveLength(1);

    store.applyRemote(
      { action: "delete", cookies: [makeCookie()], lamportTs: 5 },
      "device-a",
    );
    expect(store.getAll()).toHaveLength(0);
  });

  it("tracks local changes with Lamport clock", () => {
    const store = new CookieStore();
    const cookie = makeCookie({ value: "local" });
    const ts = store.setLocal(cookie, "my-device");
    expect(ts).toBe(1);
    expect(store.getAll()).toHaveLength(1);
    expect(store.currentTs).toBe(1);

    const ts2 = store.setLocal(makeCookie({ name: "other", value: "x" }), "my-device");
    expect(ts2).toBe(2);
  });

  it("advances Lamport clock on remote apply", () => {
    const store = new CookieStore();
    store.applyRemote(
      { action: "set", cookies: [makeCookie()], lamportTs: 100 },
      "device-x",
    );
    // Clock should be max(0, 100) + 1 = 101
    expect(store.currentTs).toBe(101);
  });

  it("tracks different cookies by domain|name|path", () => {
    const store = new CookieStore();
    store.applyRemote(
      { action: "set", cookies: [makeCookie({ domain: "a.com", name: "s1" })], lamportTs: 1 },
      "d1",
    );
    store.applyRemote(
      { action: "set", cookies: [makeCookie({ domain: "b.com", name: "s1" })], lamportTs: 1 },
      "d1",
    );
    expect(store.getAll()).toHaveLength(2);
  });
});