gitmost/apps/server/src/collaboration/collaboration.handler.spec.ts

import * as Y from 'yjs';
import { CollaborationHandler } from './collaboration.handler';
import * as yjsUtil from './yjs.util';
import { User } from '@docmost/db/types/entity.types';

/**
 * Unit tests for the `applyCommentSuggestion` collab handler (phase 3 of #315).
 *
 * The handler runs `replaceYjsMarkedText` inside the owning instance's Y
 * transaction and returns the verdict to the caller. We exercise it against a
 * REAL in-memory Y.Doc carrying a marked comment run, driven through a FAKE
 * hocuspocus whose openDirectConnection().transact(fn) simply runs fn(doc) —
 * mirroring how the real hocuspocus DirectConnection invokes the callback with
 * the shared document (it does not forward the callback's return value, which is
 * exactly why withYdocConnection captures it via a closure).
 */

// Build a Y.Doc with a single paragraph whose text carries a `comment` mark for
// the given commentId — the shape `replaceYjsMarkedText` walks in production.
function buildDocWithComment(text: string, commentId: string) {
  const doc = new Y.Doc();
  const fragment = doc.getXmlFragment('default');
  const paragraph = new Y.XmlElement('paragraph');
  const xmlText = new Y.XmlText();
  xmlText.insert(0, text);
  xmlText.format(0, text.length, { comment: { commentId, resolved: false } });
  paragraph.insert(0, [xmlText]);
  fragment.insert(0, [paragraph]);
  return doc;
}

// Fake hocuspocus exposing only what withYdocConnection needs: a direct
// connection whose transact() runs the callback against `doc`.
function fakeHocuspocus(doc: Y.Doc) {
  const connection = {
    transact: jest.fn(async (fn: (d: Y.Doc) => void) => {
      fn(doc);
    }),
    disconnect: jest.fn(async () => {}),
  };
  const hocuspocus = {
    openDirectConnection: jest.fn(async () => connection),
  } as any;
  return { hocuspocus, connection };
}

const user = { id: 'u1' } as unknown as User;

describe('CollaborationHandler.applyCommentSuggestion', () => {
  it('applies the replacement and returns the verdict when the marked text matches', async () => {
    const doc = buildDocWithComment('Hello world', 'c1');
    const { hocuspocus, connection } = fakeHocuspocus(doc);
    const handler = new CollaborationHandler();
    const handlers = handler.getHandlers(hocuspocus);

    const result = await handlers.applyCommentSuggestion('doc-1', {
      commentId: 'c1',
      expectedText: 'Hello world',
      newText: 'Goodbye world',
      user,
    });

    expect(result).toEqual({ applied: true, currentText: 'Goodbye world' });
    // The mutation ran inside the transaction and hit the real doc.
    expect(connection.transact).toHaveBeenCalledTimes(1);
    expect(connection.disconnect).toHaveBeenCalledTimes(1);
    expect(doc.getXmlFragment('default').toString()).toContain(
      'Goodbye world',
    );
  });

  it('rejects (applied=false) and returns the current text when it changed', async () => {
    const doc = buildDocWithComment('Hello world', 'c1');
    const { hocuspocus } = fakeHocuspocus(doc);
    const handler = new CollaborationHandler();
    const handlers = handler.getHandlers(hocuspocus);

    const result = await handlers.applyCommentSuggestion('doc-1', {
      commentId: 'c1',
      expectedText: 'Stale expected text',
      newText: 'Goodbye world',
      user,
    });

    expect(result).toEqual({ applied: false, currentText: 'Hello world' });
    // Nothing was replaced.
    expect(doc.getXmlFragment('default').toString()).toContain(
      'Hello world',
    );
  });

  it('forwards the exact args to replaceYjsMarkedText and returns its result', async () => {
    const doc = buildDocWithComment('abc', 'c9');
    const { hocuspocus } = fakeHocuspocus(doc);
    const spy = jest
      .spyOn(yjsUtil, 'replaceYjsMarkedText')
      .mockReturnValue({ applied: true, currentText: 'xyz' });
    const handler = new CollaborationHandler();
    const handlers = handler.getHandlers(hocuspocus);

    const result = await handlers.applyCommentSuggestion('doc-1', {
      commentId: 'c9',
      expectedText: 'abc',
      newText: 'xyz',
      user,
    });

    expect(spy).toHaveBeenCalledWith(
      doc.getXmlFragment('default'),
      'c9',
      'abc',
      'xyz',
    );
    expect(result).toEqual({ applied: true, currentText: 'xyz' });
    spy.mockRestore();
  });

  it('withYdocConnection returns the callback result (transact does not forward it)', async () => {
    const doc = new Y.Doc();
    const { hocuspocus } = fakeHocuspocus(doc);
    const handler = new CollaborationHandler();

    const value = await handler.withYdocConnection(
      hocuspocus,
      'doc-1',
      {},
      () => 42,
    );

    expect(value).toBe(42);
  });
});