ci: run the e2e suite on pull requests that are ready for review

.github/workflows/e2e-tests.yml

@@ -1,4 +1,4 @@
-name: E2E (manual)
+name: E2E
 
 on:
   workflow_dispatch:
@@ -7,23 +7,68 @@ on:
         description: Ceros dev environment to target (experience URLs + API host derive from it)
         type: string
         default: latest
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    paths:
+      - ceros.php
+      - includes/**
+      - src/**
+      - public/**
+      - package.json
+      - package-lock.json
+      - .wp-env.json
+      - tests/e2e/**
+      - .github/workflows/e2e-tests.yml
+  # Saves the npm cache on main, the only branch every PR can restore from.
+  push:
+    branches: [main]
+    paths:
+      - package-lock.json
+      - tests/e2e/package-lock.json
+      - .github/workflows/e2e-tests.yml
 
 permissions:
   contents: read
 
 concurrency:
-  group: e2e-${{ github.ref }}
+  group: e2e-${{ github.event_name }}-${{ github.ref }}
   cancel-in-progress: true
 
 jobs:
+  warm-cache:
+    name: Save the npm cache
+    if: github.event_name == 'push'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Set up Node
+        uses: actions/setup-node@v5
+        with:
+          node-version: '22'
+          cache: npm
+          cache-dependency-path: |
+            package-lock.json
+            tests/e2e/package-lock.json
+
+      - name: Install dependencies
+        run: |
+          npm ci
+          npm ci --prefix tests/e2e
+
   e2e:
     name: Playwright e2e (wp-env + real Ceros env)
+    # Not on drafts, and not on fork PRs, which get no secrets.
+    if: >-
+      github.event_name == 'workflow_dispatch' ||
+      (github.event_name == 'pull_request' && !github.event.pull_request.draft &&
+       github.event.pull_request.head.repo.full_name == github.repository)
     runs-on: ubuntu-latest
     timeout-minutes: 35
     env:
       # wp-env's dev port (also the suite default).
       BASE_URL: http://localhost:8888
-      E2E_CEROS_ENV: ${{ inputs.ceros_env }}
+      E2E_CEROS_ENV: ${{ inputs.ceros_env || 'latest' }}
     steps:
       - uses: actions/checkout@v5
 

tests/e2e/README.md

@@ -3,8 +3,9 @@
 Playwright tests for the Ceros block in the WordPress editor and on the published page,
 run against a local `wp-env` instance.
 
-**Not wired into CI or the pre-push hook, and not a required check.** These need WordPress,
-Docker and network access, which the pre-push hook explicitly rules out. See [CI](#ci) below.
+**Runs in CI on pull requests that are ready for review, but is not a required check or part of
+the pre-push hook.** These need WordPress, Docker and network access, which the pre-push hook
+explicitly rules out. See [CI](#ci) below.
 
 ## Prerequisites
 
@@ -172,8 +173,13 @@ not extend a shared base class, because at this size it would hold nothing.
 
 ## CI
 
-The suite is not wired into CI and is not a required check — it spans two products (the
-plugin and Ceros), and that ownership is unresolved. Running it anywhere, CI or another
+`e2e-tests.yml` runs the suite on pull requests from this repository once they are ready for
+review and change the plugin, its build inputs or the suite. Drafts and fork pull requests are
+skipped, since a fork gets no secrets. A new push cancels the run it replaces. It can also be
+run by hand against another Ceros environment (`ceros_env`).
+
+It is not a required check: it spans two products (the plugin and Ceros), and that ownership
+is unresolved. Running it anywhere, CI or another
 machine, needs the same inputs as a local run: `E2E_CEROS_ENV`, the secret `E2E_CEROS_API_KEY`,
 network access to that environment, and a pinned WordPress version (`.wp-env.json` leaves core
 unset, which has resolved to a version with no tag in the mirror).