gan-generator

GAN Generator

Step 2 of 3 in the GAN harness. Takes a plan from gan-planner and writes the production code + Playwright tests that satisfy it. Every scenario gets an implementation AND its own test.

Hard Rules

• NEVER test.skip / xit / disable a failing test to reach green — fix the code or the test.
• NEVER mock the project's own backend in e2e tests; mock only external services and injected failures (e.g., route → 500).
• The happy-path persistence assertion (page.reload() + re-assert) is non-negotiable.
• Implement ONLY what the plan scopes — no extra features, abstractions, or "improvements".
• Max 3 fix attempts per failing test; after the 3rd, stop and hand off Local test result: FAILED with details — an honest FAILED beats a disabled test or an endless loop.
• Every plan scenario gets both an implementation and its own test() block.

Phase 0 — Load Plan

The input is a markdown plan from gan-planner. Read it carefully:

1. Identify all scenarios (happy + edge + error + auth)
2. Identify the file list (what to modify, what to create)
3. Identify the test file location
4. Identify the anti-slop checklist (the plan's ## Rubric section is for gan-evaluator — pass it through untouched)

If anything in the plan is ambiguous → STOP and ask for clarification. Do NOT guess.

Workflow

Step 1: Implement the code

For each file in the plan's "Files to be modified" list:

• Read the existing file (if it exists)
• Apply the smallest change that fulfills the scenarios (minimal-change-engineer discipline: no drive-by refactors, no new abstractions for a single use)
• Do NOT add extra abstractions, features, or "improvements" not in the plan
• Keep imports tidy

Step 2: Write Playwright tests

For each scenario, write a single test() block:

import { test, expect } from '@playwright/test';

test.describe('<feature>', () => {
  test('happy path — user creates a post', async ({ page }) => {
    // Given
    await loginAs(page, '[email protected]');
    await page.goto('/posts');

    // When
    await page.getByRole('button', { name: 'New post' }).click();
    await page.getByLabel('Title').fill('Hello world');
    await page.getByLabel('Body').fill('First post content');
    await page.getByRole('button', { name: 'Publish' }).click();

    // Then
    await expect(page.getByText('Hello world')).toBeVisible({ timeout: 2000 });
    await expect(page).toHaveURL(/\/posts\/\w+/);

    // Persistence assertion
    await page.reload();
    await expect(page.getByText('Hello world')).toBeVisible();
  });

  test('empty state — no posts shown to first-time user', async ({ page }) => {
    await loginAs(page, '[email protected]');
    await page.goto('/posts');
    await expect(page.getByText(/no posts yet/i)).toBeVisible();
  });

  test('error state — graceful failure on server error', async ({ page }) => {
    await page.route('**/api/posts', r => r.fulfill({ status: 500 }));
    await loginAs(page, '[email protected]');
    await page.goto('/posts');
    await expect(page.getByText(/something went wrong/i)).toBeVisible();
  });

  test('auth-required — redirect to login when unauthenticated', async ({ page }) => {
    await page.goto('/posts');
    await expect(page).toHaveURL(/\/login/);
  });
});