ci: add helm chart-testing and unittest workflow

Adds a `helm` GitHub Actions workflow that runs `ct lint` and
`helm-unittest` against the gpu-operator chart on PRs that touch
`deployments/`, plus a unit-test suite (with snapshots) covering the
chart's core templates so chart regressions are caught in CI.

Workflow:
- `lint` job runs `ct lint` (with `--validate-maintainers=false` since
  the chart doesn't declare maintainers) using `CHART_DIR=deployments`.
- `unittest` job installs `helm-unittest v1.0.3` and runs
  `helm unittest deployments/gpu-operator`.
- Triggers only on PRs that change `deployments/gpu-operator/**`.

Tests cover: operator deployment, ClusterPolicy, RBAC, NodeFeatureRules,
NvidiaDriver, MIG/DCGM/device-plugin custom configs, cleanup and upgrade
CRD hooks, OpenShift readonly-fs SCC, extra objects, and input
validations. Snapshots are committed under `__snapshot__/`.

Also:
- Fix yamllint comment-spacing in `values.yaml` so `ct lint` passes.
- Add `tests/` to `.helmignore` so unittest fixtures and snapshots are
  excluded from the packaged chart.

Signed-off-by: Giulio Calzolari <gcalzolari@nvidia.com>

Author: giuliocalzo

.github/workflows/helm.yaml

@@ -0,0 +1,54 @@
+---
+name: helm
+
+on:
+  pull_request:
+    branches: [main]
+    paths:
+      - 'deployments/gpu-operator/**'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+env:
+  CHART_NAME: gpu-operator
+  CHART_DIR: deployments
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+
+      - name: Set up chart-testing
+        uses: helm/chart-testing-action@6ec842c01de15ebb84c8627d2744a0c2f2755c9f # v2.8.0
+
+      - name: Run chart-testing (lint)
+        run: |
+          ct lint \
+            --target-branch ${{ github.event.repository.default_branch }} \
+            --all \
+            --validate-maintainers=false \
+            --chart-dirs ${{ env.CHART_DIR }}
+
+  unittest:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+
+      - name: Set up Helm
+        uses: azure/setup-helm@dda3372f752e03dde6b3237bc9431cdc2f7a02a2 # v5
+
+      - name: Install helm-unittest plugin
+        run: |
+          echo "Installing helm-unittest plugin..."
+          helm plugin install https://github.com/helm-unittest/helm-unittest.git --verify=false --version v1.0.3 # 6f82a998e0b5461762ca959f87f5dd344af5e4eb
+
+      - name: Run helm unittest
+        run: helm unittest ${{ env.CHART_DIR }}/${{ env.CHART_NAME }}

deployments/gpu-operator/.helmignore

@@ -20,3 +20,5 @@
 .idea/
 *.tmproj
 .vscode/
+# helm unittest
+tests/

deployments/gpu-operator/tests/__snapshot__/cleanup_crd_test.yaml.snap

@@ -0,0 +1,48 @@
+should match snapshot:
+  1: |
+    apiVersion: batch/v1
+    kind: Job
+    metadata:
+      annotations:
+        helm.sh/hook: pre-delete
+        helm.sh/hook-delete-policy: hook-succeeded,before-hook-creation
+        helm.sh/hook-weight: "1"
+      labels:
+        app.kubernetes.io/component: gpu-operator
+        app.kubernetes.io/instance: gpu-operator
+        app.kubernetes.io/managed-by: Helm
+        app.kubernetes.io/name: gpu-operator
+        app.kubernetes.io/version: v25.0.0
+        helm.sh/chart: gpu-operator-v1.0.0-devel
+      name: gpu-operator-cleanup-crd
+      namespace: gpu-operator
+    spec:
+      template:
+        metadata:
+          labels:
+            app.kubernetes.io/component: gpu-operator
+            app.kubernetes.io/instance: gpu-operator
+            app.kubernetes.io/managed-by: Helm
+            app.kubernetes.io/name: gpu-operator
+            app.kubernetes.io/version: v25.0.0
+            helm.sh/chart: gpu-operator-v1.0.0-devel
+          name: gpu-operator-cleanup-crd
+        spec:
+          containers:
+            - args:
+                - delete
+                - --filepath=/opt/gpu-operator/nvidia.com_clusterpolicies.yaml
+                - --filepath=/opt/gpu-operator/nvidia.com_nvidiadrivers.yaml
+                - --filepath=/opt/gpu-operator/nfd-api-crds.yaml
+              command:
+                - /usr/bin/manage-crds
+              image: nvcr.io/nvidia/gpu-operator:v25.0.0
+              imagePullPolicy: IfNotPresent
+              name: cleanup-crd
+          restartPolicy: OnFailure
+          serviceAccountName: gpu-operator
+          tolerations:
+            - effect: NoSchedule
+              key: node-role.kubernetes.io/control-plane
+              operator: Equal
+              value: ""