[Bug]: update snapshots not creating good diffs

[debs-obrien]

Version

1.51.0-alpha-2025-01-22

Steps to reproduce

1. create the follwing test:

test('test', async ({ page }) => {
  await page.goto('https://debs-obrien.github.io/playwright-movies-app/movie?id=533535&page=1');
  await expect(page.getByRole('main')).toMatchAriaSnapshot(``);
});

2. run test using the play button in vscode extension

3. run 'git apply test-results/rebaselines.patch'

4. change the page source so snapshots will differ. This is done by modifying the movie id. The code snippet below shows a goto with a url containing a different id. Use this snippet or just manually edit the movie id to be 718821

test('test', async ({ page }) => {
  await page.goto('https://debs-obrien.github.io/playwright-movies-app/movie?id=718821&page=1');
  await expect(page.getByRole('main')).toMatchAriaSnapshot(``);
});

5. run test again in vscode.
6. run git apply test-results/rebaselines.patch

Expected behavior

should be good diff

Actual behavior

patch with only garbage at line 4

Additional context

Note running with --update-source-method 3-way is also not working so best way to see whats happening is to check diff in test results folder

Environment

System:
    OS: macOS 15.2
    CPU: (10) arm64 Apple M1 Max
    Memory: 236.09 MB / 64.00 GB
  Binaries:
    Node: 20.11.1 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.2.4 - /usr/local/bin/npm
    pnpm: 8.5.0 - /usr/local/bin/pnpm
  IDEs:
    VSCode: 1.96.4 - /usr/local/bin/code
  Languages:
    Bash: 3.2.57 - /bin/bash
  npmPackages:
    @playwright/test: ^1.51.0-alpha-2025-01-22 => 1.51.0-alpha-2025-01-22

[debs-obrien]

running tests using npx playwright test instead of vscode extension doesn't create diff for a test that has been modified so behaviour is different

[pavelfeldman]

How can I do (4)? I don't think that if I modify source (which source?) https://debs-obrien.github.io/playwright-movies-app/movie?id=718821&page=1 will magically update. Please follow the issue template to file something I can reproduce locally.

[debs-obrien]

i updated the steps to give clearer instructions for step 4