murashit_codex-panel/tests/features/chat/fork.test.ts

import { describe, expect, it } from "vitest";

import { forkCandidatesFromItems, isForkCandidateItem, turnsAfterTurnId } from "../../../src/features/chat/fork";
import type { DisplayItem } from "../../../src/features/chat/display/types";

describe("fork candidates", () => {
  it("selects final assistant messages and counts later turns", () => {
    const items: DisplayItem[] = [
      { id: "u1", kind: "message", role: "user", text: "first", turnId: "turn-1", markdown: true },
      { id: "a1", kind: "message", role: "assistant", text: "first answer", turnId: "turn-1", markdown: true },
      { id: "tool-1", kind: "tool", role: "tool", text: "work", turnId: "turn-2" },
      { id: "a2-delta", kind: "message", role: "assistant", text: "draft", turnId: "turn-2", markdown: false },
      { id: "a2", kind: "message", role: "assistant", text: "second answer", turnId: "turn-2", markdown: true },
      { id: "u3", kind: "message", role: "user", text: "third", turnId: "turn-3", markdown: true },
      { id: "a3", kind: "message", role: "assistant", text: "third answer", turnId: "turn-3", markdown: true },
    ];

    const candidates = forkCandidatesFromItems(items);

    expect(candidates).toEqual([
      { itemId: "a1", turnId: "turn-1" },
      { itemId: "a2", turnId: "turn-2" },
      { itemId: "a3", turnId: "turn-3" },
    ]);
    expect(isForkCandidateItem(expectPresent(items[4]), candidates)).toBe(true);
    expect(isForkCandidateItem(expectPresent(items[3]), candidates)).toBe(false);
    expect(turnsAfterTurnId(items, "turn-1")).toBe(2);
    expect(turnsAfterTurnId(items, "turn-2")).toBe(1);
    expect(turnsAfterTurnId(items, "turn-3")).toBe(0);
    expect(turnsAfterTurnId(items, "missing")).toBeNull();
  });
});

function expectPresent<T>(value: T | null | undefined): T {
  if (value === null || value === undefined) throw new Error("Expected value to be present");
  return value;
}