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update-int-snapshots

amir20/dozzle/.claude/skills/update-int-snapshots/SKILL.md

Use when Playwright visual snapshots in e2e/visual.spec.ts-snapshots/ need to be regenerated after a UI change (logo, theme, layout, anything that affects rendered pixels) and the integration suite needs to be rerun via make int

Skill15k starsChanged 11 days ago

What's in it

  1. Update Integration Snapshots
  2. When to Use
  3. Procedure
  4. Common Mistakes
  5. Quick Reference
---
name: update-int-snapshots
description: Use when Playwright visual snapshots in e2e/visual.spec.ts-snapshots/ need to be regenerated after a UI change (logo, theme, layout, anything that affects rendered pixels) and the integration suite needs to be rerun via make int
---

# Update Integration Snapshots

## When to Use

- A visual change landed (logo, color, spacing, fonts) and `make int` will fail on `visual.spec.ts` until snapshots are regenerated.
- A snapshot test reports diffs you've confirmed are intentional.

Do NOT use when diffs are unintentional regressions — investigate first.

## Procedure

1. **Delete the stale snapshots** so Playwright writes fresh ones (don't try to update in place, the old PNGs can confuse the diff):

   ```bash
   rm e2e/visual.spec.ts-snapshots/*.png
   ```

2. **Run with `--update-snapshots` via `compose up`.** You must use `compose up` (not `compose run`) because the navigation sidebar snapshot includes the live container list, and the two modes produce different sibling containers. The cleanest way is to patch the playwright command in `docker-compose.yml` temporarily:

   ```bash
   sed -i.bak 's|command: npx --yes playwright test|command: npx --yes playwright test --update-snapshots|' docker-compose.yml
   make int
   mv docker-compose.yml.bak docker-compose.yml
   ```

   Snapshots must be generated in Linux/Chromium (the compose image), not macOS, because filenames include the platform suffix (e.g. `-chromium-linux.png`).

   Nothing needs clearing first. The compose file publishes no host ports, every container is named `dozzle_e2e_*` under the fixed project `dozzle_e2e`, and filters match those names exactly. Other containers on the machine can't block the run or show up in the snapshots, and a leftover run from another worktree is recreated. Two worktrees running `make int` at the same time do still clobber each other, so run one at a time.

3. **Verify** by rerunning the normal suite:

   ```bash
   make int
   ```

   Should now pass cleanly.

4. **Commit the regenerated PNGs** alongside the UI change so CI stays green.

## Common Mistakes

- **Running `npx playwright test --update-snapshots` locally on macOS.** Generates `-darwin` filenames CI doesn't use. Always go through the docker compose image.
- **Forgetting to delete first.** `--update-snapshots` does overwrite, but if the test layout changed (new test, renamed snapshot), stale PNGs are left behind. Wipe-and-regenerate is safest.
- **Adding a test container without the prefix, or a filter without anchors.** `name=dozzle` is a substring match and pulls in any local container with "dozzle" in its name. Use `container_name: dozzle_e2e_<service>` and `DOZZLE_FILTER=name=^dozzle_e2e_<service>$$` (`$$` escapes `$` in compose).
- **Publishing a host port "for debugging".** It brings back conflicts with whatever else is on the machine. Reach instances by service name from inside the network.

## Quick Reference

```bash
rm e2e/visual.spec.ts-snapshots/*.png
sed -i.bak 's|command: npx --yes playwright test|& --update-snapshots|' docker-compose.yml
make int
mv docker-compose.yml.bak docker-compose.yml
make int   # verify pass
```

More agent context in amir20/dozzle

3 other files this repository gives its agents.

CLAUDE.md

Skill

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