vscode-cowriting-plugin/test/pendingEdits.test.ts

import { describe, it, expect } from "vitest";
import { minimizeReplace, PendingEditRegistry } from "../src/pendingEdits";
import type { Provenance } from "../src/model";

const AGENT: Provenance = {
  kind: "agent", id: "claude",
  agent: { sdk: "@cline/sdk", model: "sonnet", sessionId: "run-1" },
};

describe("PendingEditRegistry (INV-9)", () => {
  it("matches and consumes a single-hunk event equal to the registration", () => {
    const reg = new PendingEditRegistry();
    reg.register({
      docPath: "d.md", start: 3, end: 7, newText: "new", provenance: AGENT, turnId: "t1",
      full: { start: 3, end: 7, newLength: 3 },
    });
    const hit = reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 3 }]);
    expect(hit?.turnId).toBe("t1");
    expect(reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 3 }])).toBeNull();
  });
  it("matches a HOST-SPLIT event: several hunks inside the full range with the same net delta", () => {
    // The host word-diffs one applied replace into multiple minimal hunks
    // (observed on F4 accept) — per-hunk equality misses; net-effect matches.
    const reg = new PendingEditRegistry();
    reg.register({
      docPath: "d.md", start: 10, end: 50, newText: "x".repeat(45), provenance: AGENT, turnId: "t2",
      full: { start: 10, end: 50, newLength: 45 },
    });
    const hit = reg.matchEvent("d.md", [
      { start: 12, end: 20, newLength: 9 },
      { start: 25, end: 30, newLength: 6 },
      { start: 40, end: 48, newLength: 11 },
    ]);
    expect(hit?.turnId).toBe("t2");
  });
  it("does not match a different doc, hunks outside the full range, or a different delta", () => {
    const reg = new PendingEditRegistry();
    reg.register({
      docPath: "d.md", start: 3, end: 7, newText: "new", provenance: AGENT,
      full: { start: 3, end: 7, newLength: 3 },
    });
    expect(reg.matchEvent("other.md", [{ start: 3, end: 7, newLength: 3 }])).toBeNull();
    expect(reg.matchEvent("d.md", [{ start: 3, end: 8, newLength: 4 }])).toBeNull();
    expect(reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 4 }])).toBeNull();
    expect(reg.matchEvent("d.md", [])).toBeNull();
  });
  it("falls back to the minimized range when no full extent was registered", () => {
    const reg = new PendingEditRegistry();
    reg.register({ docPath: "d.md", start: 3, end: 7, newText: "new", provenance: AGENT });
    expect(reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 3 }])).not.toBeNull();
  });
  it("unregister removes a failed application", () => {
    const reg = new PendingEditRegistry();
    const p = { docPath: "d.md", start: 0, end: 0, newText: "x", provenance: AGENT };
    reg.register(p);
    reg.unregister(p);
    expect(reg.matchEvent("d.md", [{ start: 0, end: 0, newLength: 1 }])).toBeNull();
  });
  it("unregister reports whether the registration was still pending", () => {
    const reg = new PendingEditRegistry();
    const p = { docPath: "d.md", start: 0, end: 0, newText: "x", provenance: AGENT };
    reg.register(p);
    expect(reg.unregister(p)).toBe(true);
    reg.register(p);
    reg.matchEvent("d.md", [{ start: 0, end: 0, newLength: 1 }]);
    expect(reg.unregister(p)).toBe(false);
  });
});

describe("minimizeReplace (host diff-minimization mirror)", () => {
  it("trims a common suffix (the E2E-observed case)", () => {
    expect(minimizeReplace("target sentence", "REWRITTEN-BY-CLAUDE sentence")).toEqual({ prefix: 0, suffix: 9 });
  });
  it("trims a common prefix", () => {
    expect(minimizeReplace("Hello world", "Hello there")).toEqual({ prefix: 6, suffix: 0 });
  });
  it("trims both, never overlapping", () => {
    expect(minimizeReplace("aba", "aa")).toEqual({ prefix: 1, suffix: 1 });
    expect(minimizeReplace("aaaa", "aa")).toEqual({ prefix: 2, suffix: 0 });
  });
  it("identical texts minimize to nothing", () => {
    expect(minimizeReplace("same", "same")).toEqual({ prefix: 4, suffix: 0 });
  });
  it("disjoint texts trim nothing", () => {
    expect(minimizeReplace("abc", "xyz")).toEqual({ prefix: 0, suffix: 0 });
  });
});