diff --git a/.github/workflows/helm-lint.yaml b/.github/workflows/helm-lint.yaml
new file mode 100644
index 0000000..8498f12
--- /dev/null
+++ b/.github/workflows/helm-lint.yaml
@@ -0,0 +1,44 @@
+# NOTE: This workflow can be run locally using https://github.com/nektos/act with:
+# act -W .github/workflows/helm-lint.yaml workflow_call -s GITHUB_TOKEN=$(gh auth token)
+name: Helm Lint
+on:
+  workflow_call:
+    inputs:
+      ref:
+        type: string
+        description: The Git ref under test.
+        required: true
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.ref }}
+          fetch-depth: 0
+
+      - name: Set up Helm
+        uses: azure/setup-helm@v4
+        with:
+          version: v3.15.3
+
+      - name: Set up chart-testing
+        uses: helm/chart-testing-action@v2
+
+      - name: Run chart-testing (lint)
+        run: |-
+          ct lint \
+            --target-branch ${{ github.event.repository.default_branch }} \
+            --charts chart/ \
+            --validate-maintainers=false
+
+      - name: Run template validation
+        run: |-
+          helm template foo chart \
+            | docker run -i --rm ghcr.io/yannh/kubeconform:latest \
+            --strict --summary
+
+      - name: Run manifest snapshot test
+        run: docker run -i --rm -v $(pwd):/apps helmunittest/helm-unittest chart
diff --git a/.github/workflows/test-pr.yaml b/.github/workflows/test-pr.yaml
index 72aa987..be2a1a6 100644
--- a/.github/workflows/test-pr.yaml
+++ b/.github/workflows/test-pr.yaml
@@ -31,15 +31,22 @@ jobs:
     with:
       ref: ${{ github.event.pull_request.head.sha }}
 
+  # Run the chart linting on every PR, even from external repos
+  helm_lint:
+    uses: ./.github/workflows/helm-lint.yaml
+    with:
+      ref: ${{ github.event.pull_request.head.sha }}
+
   # This job exists so that PRs from outside the main repo are rejected
   fail_on_remote:
+    needs: [unit_tests, helm_lint]
     runs-on: ubuntu-latest
     steps:
       - name: PR must be from a branch in the azimuth-cloud/cluster-api-addon-provider repo
         run: exit ${{ github.event.pull_request.head.repo.full_name == 'azimuth-cloud/cluster-api-addon-provider' && '0' || '1' }}
 
   publish_artifacts:
-    needs: [unit_tests,fail_on_remote]
+    needs: [fail_on_remote]
     uses: ./.github/workflows/build-push-artifacts.yaml
     with:
       ref: ${{ github.event.pull_request.head.sha }}
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..1e97e73
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,22 @@
+# Contributing
+
+We welcome contributions and suggestions for improvements to this code base.
+Please check for relevant issues and PRs before opening a new one of your own.
+
+## Making a contribution
+
+### Helm template snapshots
+
+The CI in this repository uses the Helm
+[unittest](https://github.com/helm-unittest/helm-unittest) plugin's
+snapshotting functionality to check PRs for changes to the templated manifests.
+Therefore, if your PR makes changes to the manifest templates or values, you
+will need to update the saved snapshots to allow your changes to pass the
+automated tests. The easiest way to do this is to run the `helm unittest` command
+inside a docker container from the repo root.
+
+```
+docker run -i --rm -v $(pwd):/apps helmunittest/helm-unittest chart -u
+```
+
+where the `-u` option is used to update the existing snapshots.
diff --git a/chart/.helmignore b/chart/.helmignore
index 0e8a0eb..10a0506 100644
--- a/chart/.helmignore
+++ b/chart/.helmignore
@@ -21,3 +21,5 @@
 .idea/
 *.tmproj
 .vscode/
+# Helm unit test files
+tests/
diff --git a/chart/tests/__snapshot__/snapshot_test.yaml.snap b/chart/tests/__snapshot__/snapshot_test.yaml.snap
new file mode 100644
index 0000000..d863727
--- /dev/null
+++ b/chart/tests/__snapshot__/snapshot_test.yaml.snap
@@ -0,0 +1,179 @@
+templated manifests should match snapshot:
+  1: |
+    apiVersion: rbac.authorization.k8s.io/v1
+    kind: ClusterRole
+    metadata:
+      labels:
+        app.kubernetes.io/instance: RELEASE-NAME
+        app.kubernetes.io/managed-by: Helm
+        app.kubernetes.io/name: cluster-api-addon-provider
+        app.kubernetes.io/version: main
+        helm.sh/chart: cluster-api-addon-provider-0.1.0
+      name: RELEASE-NAME-cluster-api-addon-provider
+    rules:
+      - apiGroups:
+          - apiextensions.k8s.io
+        resources:
+          - customresourcedefinitions
+        verbs:
+          - list
+          - get
+          - watch
+          - create
+      - apiGroups:
+          - apiextensions.k8s.io
+        resourceNames:
+          - helmreleases.addons.stackhpc.com
+          - manifests.addons.stackhpc.com
+        resources:
+          - customresourcedefinitions
+        verbs:
+          - update
+          - patch
+      - apiGroups:
+          - ""
+        resources:
+          - namespaces
+        verbs:
+          - list
+          - watch
+      - apiGroups:
+          - ""
+          - events.k8s.io
+        resources:
+          - events
+        verbs:
+          - create
+      - apiGroups:
+          - addons.stackhpc.com
+        resources:
+          - '*'
+        verbs:
+          - '*'
+      - apiGroups:
+          - cluster.x-k8s.io
+        resources:
+          - clusters
+        verbs:
+          - list
+          - watch
+          - get
+      - apiGroups:
+          - infrastructure.cluster.x-k8s.io
+        resources:
+          - '*'
+        verbs:
+          - list
+          - watch
+          - get
+      - apiGroups:
+          - ""
+        resources:
+          - configmaps
+          - secrets
+        verbs:
+          - list
+          - watch
+          - get
+          - patch
+  2: |
+    apiVersion: rbac.authorization.k8s.io/v1
+    kind: ClusterRoleBinding
+    metadata:
+      labels:
+        app.kubernetes.io/instance: RELEASE-NAME
+        app.kubernetes.io/managed-by: Helm
+        app.kubernetes.io/name: cluster-api-addon-provider
+        app.kubernetes.io/version: main
+        helm.sh/chart: cluster-api-addon-provider-0.1.0
+      name: RELEASE-NAME-cluster-api-addon-provider
+    roleRef:
+      apiGroup: rbac.authorization.k8s.io
+      kind: ClusterRole
+      name: RELEASE-NAME-cluster-api-addon-provider
+    subjects:
+      - kind: ServiceAccount
+        name: RELEASE-NAME-cluster-api-addon-provider
+        namespace: NAMESPACE
+  3: |
+    apiVersion: v1
+    data:
+      config.yaml: |
+        !include "/etc/capi-addon-provider/defaults.yaml,/etc/capi-addon-provider/user-config.yaml"
+      defaults.yaml: |
+        easykubeFieldManager: RELEASE-NAME-cluster-api-addon-provider
+      user-config.yaml: |
+        {}
+    kind: ConfigMap
+    metadata:
+      labels:
+        app.kubernetes.io/instance: RELEASE-NAME
+        app.kubernetes.io/managed-by: Helm
+        app.kubernetes.io/name: cluster-api-addon-provider
+        app.kubernetes.io/version: main
+        helm.sh/chart: cluster-api-addon-provider-0.1.0
+      name: RELEASE-NAME-cluster-api-addon-provider
+  4: |
+    apiVersion: apps/v1
+    kind: Deployment
+    metadata:
+      labels:
+        app.kubernetes.io/instance: RELEASE-NAME
+        app.kubernetes.io/managed-by: Helm
+        app.kubernetes.io/name: cluster-api-addon-provider
+        app.kubernetes.io/version: main
+        helm.sh/chart: cluster-api-addon-provider-0.1.0
+      name: RELEASE-NAME-cluster-api-addon-provider
+    spec:
+      replicas: 1
+      selector:
+        matchLabels:
+          app.kubernetes.io/instance: RELEASE-NAME
+          app.kubernetes.io/name: cluster-api-addon-provider
+      strategy:
+        type: Recreate
+      template:
+        metadata:
+          annotations:
+            addons.stackhpc.com/config-hash: ae07aeabb7cd21042b32369ecbc49a27c81ef80948939f1676d4ac9530ab60e4
+          labels:
+            app.kubernetes.io/instance: RELEASE-NAME
+            app.kubernetes.io/name: cluster-api-addon-provider
+        spec:
+          containers:
+            - image: ghcr.io/azimuth-cloud/cluster-api-addon-provider:main
+              imagePullPolicy: IfNotPresent
+              name: cluster-api-addon-provider
+              resources: {}
+              securityContext:
+                allowPrivilegeEscalation: false
+                capabilities:
+                  drop:
+                    - ALL
+                readOnlyRootFilesystem: true
+              volumeMounts:
+                - mountPath: /etc/capi-addon-provider
+                  name: etc-capi-addon-provider
+                  readOnly: true
+                - mountPath: /tmp
+                  name: tmp
+          securityContext:
+            runAsNonRoot: true
+          serviceAccountName: RELEASE-NAME-cluster-api-addon-provider
+          volumes:
+            - configMap:
+                name: RELEASE-NAME-cluster-api-addon-provider
+              name: etc-capi-addon-provider
+            - emptyDir: {}
+              name: tmp
+  5: |
+    apiVersion: v1
+    kind: ServiceAccount
+    metadata:
+      labels:
+        app.kubernetes.io/instance: RELEASE-NAME
+        app.kubernetes.io/managed-by: Helm
+        app.kubernetes.io/name: cluster-api-addon-provider
+        app.kubernetes.io/version: main
+        helm.sh/chart: cluster-api-addon-provider-0.1.0
+      name: RELEASE-NAME-cluster-api-addon-provider
diff --git a/chart/tests/snapshot_test.yaml b/chart/tests/snapshot_test.yaml
new file mode 100644
index 0000000..262562e
--- /dev/null
+++ b/chart/tests/snapshot_test.yaml
@@ -0,0 +1,7 @@
+# To update manifest snapshots run helm unittest plugin with -u option:
+# docker run -i --rm -v $(pwd):/apps helmunittest/helm-unittest -u chart
+suite: Manifest snapshot tests
+tests:
+  - it: templated manifests should match snapshot
+    asserts:
+      - matchSnapshot: {}