doc[e2e]: add README

e2e/README.md

@@ -0,0 +1,113 @@
+# E2E
+
+This action takes care of checking out OctoPrint in the specified `ref`, installing it, starting it up with an
+e2e test configuration and then running its Playwright based e2e test suite against it. 
+
+If there are any errors detected in the test suite, or found in `octoprint.log` after running the test suite, 
+the action will fail. The Playwright reports will be uploaded as artifacts, as will the log in case of logged 
+errors. The artifacts will use a suffix if configured, to support matrix setups. 
+
+To reduce runtime, the action takes care of caching Playwright's dependencies.
+
+To support e2e testing of fresh OctoPrint builds, the OctoPrint package to install can also be changed from the 
+checkout to a build.
+
+To support e2e testing plugins, additional dependencies can also be installed along side OctoPrint before the
+test suite is run.
+
+To support e2e testing against already running servers, a server endpoint can also be provided, in which case
+OctoPrint won't be installed and run.
+
+## Inputs
+
+### `ref`
+
+The OctoPrint ref to checkout, install and run tests from. `master` if not set.
+
+### `octoprint`
+
+The OctoPrint package to install. `.` if not set, so the checkout defined by `ref`. Can also be a freshly built wheel, official pypi release or similar.
+
+### `deps`
+
+Additional reps to install via `pip` alongside OctoPrint, e.g. plugins.
+
+### `python`
+
+Python version to use. `3.12` if not set.
+
+### `suffix`
+
+Suffix to use for the generated artifacts.
+
+### `server`
+
+URL of existing server to test, instead of installing and running OctoPrint from the checkout.
+
+## Usage
+
+### Testing a fresh OctoPrint build against multiple Python versions
+
+```yaml
+  test-e2e:
+    name: 🧪 E2E tests
+    needs: build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+    steps:
+      - name: ⬇ Download build result
+        uses: actions/download-artifact@v4
+        with:
+          name: dist
+          path: dist
+
+      - name: 🎭 Run E2E
+        uses: OctoPrint/actions/e2e@main
+        with:
+          ref: ${{ github.ref }}
+          octoprint: ${{ github.workspace }}/dist/*.whl
+          python: ${{ matrix.python }}
+          suffix: "-py${{ matrix.python }}"
+```
+
+### Testing various OctoPrint versions with a custom plugin installed
+
+```yaml
+  e2e:
+    name: 🧪 E2E tests
+    needs: build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        octoprint: ["master", "maintenance"]
+    steps:
+      - name: ⬇ Download build result
+        uses: actions/download-artifact@v4
+        with:
+          name: dist
+          path: dist
+
+      - name: 🎭 Run OctoPrint's E2E Tests
+        uses: OctoPrint/actions/e2e@main
+        with:
+          ref: ${{ matrix.octoprint }}
+          deps: ${{ github.workspace }}/dist/*.whl
+          suffix: "-${{ matrix.octoprint }}"
+```
+
+### Testing an already running OctoPrint
+
+```yaml
+  e2e:
+    name: "🧪 E2E"
+    runs-on: ubuntu-latest
+    needs: deploy
+    steps:
+
+    - name: "🎭 Run E2E tests"
+      uses: OctoPrint/actions/e2e@main
+      with:
+        server: http://octoprint.example.com
+```

e2e/action.yml

@@ -3,7 +3,7 @@ description: "Runs OctoPrint's E2E tests"
 
 inputs:
   ref:
-    description: "OctoPrint ref to install and run tests for"
+    description: "OctoPrint ref to check out"
     required: false
     default: master
   octoprint: