lww.test.ts · Source

lww.test.tspackages/collaboration/src/lww.test.tsraw ← src3,707 B← Back to the app
1/**
2 * TASK-0095 R1 — the LWW timestamp compare (the S12 gate's named unit test:
3 * "the two-field split: title consent vs property LWW").
4 *
5 * Pure (no UI/fetch/store) — the outbox worker + the web UI call this.
6 */
7import { describe, expect, it } from "vitest";
8import {
9  compareLwwTimestamps,
10  resolveFieldConflict,
11  type FieldVersion,
12} from "./lww.js";
13 
14const local = (value: string, ts: number): FieldVersion => ({ value, ts });
15const remote = (value: string, ts: number, author = "Ana"): FieldVersion => ({ value, ts, author });
16 
17describe("compareLwwTimestamps (the plain-LWW core)", () => {
18  it("the newer write wins (remote newer → remote; local newer → local)", () => {
19    expect(compareLwwTimestamps(1000, 2000)).toBe("remote");
20    expect(compareLwwTimestamps(2000, 1000)).toBe("local");
21  });
22  it("a tie resolves to LOCAL (the in-front-of-them intent — conservative)", () => {
23    expect(compareLwwTimestamps(1000, 1000)).toBe("local");
24  });
25});
26 
27describe("resolveFieldConflict — title = LWW-with-consent (never auto-overwrite)", () => {
28  it("a 409 on the title → the consent outcome (refetch + toast + Apply anyway), even when the local ts is newer", () => {
29    // The local write is NEWER, but a title 409 still asks the user (the CAS
30    // says the remote write already landed — silently overwriting a title is
31    // the unsafe direction).
32    const out = resolveFieldConflict("title", local("My title", 2000), remote("Their title", 1000));
33    expect(out.kind).toBe("consent");
34    if (out.kind === "consent") {
35      expect(out.applyAction).toBe("fresh-patch");
36      expect(out.localValue).toBe("My title");
37      expect(out.toast).toBe(
38        "Title was changed by Ana — your change 'My title' was not applied",
39      );
40    }
41  });
42 
43  it("the toast names the remote author (and falls back to 'someone')", () => {
44    const out = resolveFieldConflict("title", local("X", 100), remote("Y", 200));
45    expect(out).toMatchObject({ kind: "consent", toast: expect.stringContaining("Ana") });
46    const noAuthor = resolveFieldConflict("title", local("X", 100), { value: "Y", ts: 200 });
47    expect(noAuthor).toMatchObject({
48      kind: "consent",
49      toast: expect.stringContaining("someone"),
50    });
51  });
52});
53 
54describe("resolveFieldConflict — property = plain LWW (the newer timestamp wins)", () => {
55  it("the local write is newer → keep the local value (no toast)", () => {
56    const out = resolveFieldConflict("property", local("local-value", 2000), remote("remote-value", 1000));
57    expect(out).toEqual({ kind: "lww-local-wins", value: "local-value" });
58  });
59 
60  it("the remote write is newer → take the remote value + the 'Updated to the latest value' toast", () => {
61    const out = resolveFieldConflict("property", local("local-value", 1000), remote("remote-value", 2000));
62    expect(out).toEqual({
63      kind: "lww-remote-wins",
64      value: "remote-value",
65      toast: "Updated to the latest value",
66    });
67  });
68 
69  it("a tie → local wins (the conservative default, no toast)", () => {
70    const out = resolveFieldConflict("property", local("local", 1000), remote("remote", 1000));
71    expect(out).toEqual({ kind: "lww-local-wins", value: "local" });
72  });
73 
74  it("the two-field split: the SAME 409 → consent for a title, LWW for a property", () => {
75    const a = resolveFieldConflict("title", local("t", 1000), remote("r", 2000));
76    const b = resolveFieldConflict("property", local("t", 1000), remote("r", 2000));
77    expect(a.kind).toBe("consent"); // the title asks
78    expect(b.kind).toBe("lww-remote-wins"); // the property applies (newer wins)
79    expect(b).toMatchObject({ toast: "Updated to the latest value" });
80  });
81});
82