Hankan/test/domain/block-leak.test.ts

/* The ::task block leaking into the message body.

   Reported from the app: the raw text "::task translate" and its five
   sentences appeared as prose above the exercise those same lines had
   already been rendered into.

   It is lib/blocks.js, not the model. parse() removes ::words by
   truncating the body at its index, then removes ::task by substring —
   but RE.task's terminator (?:\n::|$) is part of the match, so t[0] ends
   with the "\n::" of the following ::words that the truncation just cut
   off. The substring no longer occurs, replace() is a no-op, and the whole
   task block stays in the body.

   Order is what decides it. The stub tutor emits ::words before ::task and
   is therefore fine; a real model emitted ::task first. Nothing in the
   prompt requires either order, so this was always reachable.

   The fixture is a verbatim capture from gpt-oss-20b through the server. */

import { describe, it, expect } from "vitest";
import { parse } from "@lib/blocks.js";
import { parseMessage, stripLeakedBlocks } from "@app/domain/gloss.js";

import type { ParsedMessage } from "@lib/blocks.js";

/** Narrow the Task union; only translate tasks appear in these fixtures. */
function translateItems(task: ParsedMessage["task"]): { q: string }[] {
  if (!task || task.type !== "translate") throw new Error(`expected a translate task, got ${task?.type}`);
  return task.items;
}

const CAPTURED = "::task translate\n\ub098 \uac00\ub2e4  \n\ub108 \uba39\ub2e4  \n\uc6b0\ub9ac \ub9c8\uc2dc\ub2e4  \n\uc774 \uc790\ub2e4  \n\uadf8 \ub098\ubb34 \uc11c\ub2e4  \n\n::words\n\ub098 | I, me (casual) | pron  \n\uac00\ub2e4 | to go | verb (plain)  \n\ub108 | you (casual) | pron  \n\uba39\ub2e4 | to eat | verb (plain)  \n\uc6b0\ub9ac | we, our | pron  \n\ub9c8\uc2dc\ub2e4 | to drink | verb (plain)  \n\uc774 | this | det  \n\uc790\ub2e4 | to sleep | verb (plain)  \n\uadf8 | that (near you) | det  \n\ub098\ubb34 | tree | noun  \n\uc11c\ub2e4 | to stand | verb (plain)  \n\n::progress 20";

describe("lib/blocks.js — the leak, pinned as it is", () => {
  it("leaves the whole ::task block in body when ::task precedes ::words", () => {
    const r = parse(CAPTURED);
    // The blocks themselves parse correctly...
    expect(r.task?.type).toBe("translate");
    expect(translateItems(r.task)).toHaveLength(5);
    expect(r.words).toHaveLength(11);
    // ...and the body still carries the markup that produced them.
    expect(r.body).toContain("::task translate");
    expect(r.body).toContain("나 가다");
  });

  it("is fine in the other order, which is why the stub never showed it", () => {
    const swapped = "Here you go.\n\n::words\n나 | I | pron\n\n::task translate\n나 가다\n";
    expect(parse(swapped).body).not.toContain("::task");
  });
});

describe("parseMessage — the workaround", () => {
  it("keeps the blocks and drops the leaked markup", () => {
    const r = parseMessage(CAPTURED);
    expect(r.body).not.toContain("::");
    expect(r.body).not.toContain("나 가다");
    // Nothing the blocks needed was lost.
    expect(r.task?.type).toBe("translate");
    expect(translateItems(r.task)).toHaveLength(5);
    expect(r.words).toHaveLength(11);
    expect(r.progress?.score).toBe(20);
  });

  it("keeps prose that comes before the blocks", () => {
    const r = parseMessage("좋아요. Try these.\n\n::task translate\n나 가다\n\n::words\n나 | I | pron\n");
    expect(r.body).toBe("좋아요. Try these.");
    expect(translateItems(r.task)).toHaveLength(1);
  });

  it("still handles the order the stub uses", () => {
    const r = parseMessage("Here you go.\n\n::words\n나 | I | pron\n\n::task translate\n나 가다\n");
    expect(r.body).toBe("Here you go.");
    expect(translateItems(r.task)).toHaveLength(1);
  });

  it("leaves an ordinary message alone", () => {
    const r = parseMessage("좋아요!\n\nThat is the shape of it.");
    expect(r.body).toBe("좋아요!\n\nThat is the shape of it.");
  });
});

describe("stripLeakedBlocks", () => {
  it("does nothing without a directive", () => {
    expect(stripLeakedBlocks("a\n\nb")).toBe("a\n\nb");
  });
  it("cuts from the first directive line", () => {
    expect(stripLeakedBlocks("keep\n::task translate\ndrop\n::words\ndrop")).toBe("keep");
  });
  it("does not trip on a colon that is not at the start of a line", () => {
    expect(stripLeakedBlocks("see:: this")).toBe("see:: this");
  });
});