Helm Chart Testing & CI/CD Pipeline Integra...

💡 Quick Answer: Test Helm charts automatically with ct (chart-testing), helm unittest, and GitHub Actions. Validate templates, lint values, and run integration tests before release.

The Problem

Shipping untested Helm charts leads to broken deployments. A typo in values.yaml, a missing template condition, or an incompatible Kubernetes API version can take down production. You need automated testing in CI that catches issues before they reach any cluster.

The Solution

Helm Lint (Built-in)

# Basic linting — catches YAML syntax and chart structure issues
helm lint ./my-chart
helm lint ./my-chart --values values-production.yaml
helm lint ./my-chart --set replicas=0  # Test edge cases

# Strict mode — treats warnings as errors
helm lint ./my-chart --strict

# Template rendering — verify output without deploying
helm template my-release ./my-chart --values values-production.yaml > rendered.yaml
kubectl apply --dry-run=server -f rendered.yaml

chart-testing (ct) — The Standard Tool

# Install ct
brew install chart-testing  # macOS
# or
pip install chart-testing

# Lint all changed charts (Git-aware)
ct lint --config ct.yaml

# Full integration test (installs on cluster, runs tests, cleans up)
ct install --config ct.yaml

# ct.yaml — chart-testing configuration
remote: origin
target-branch: main
chart-dirs:
  - charts
chart-repos:
  - bitnami=https://charts.bitnami.com/bitnami
helm-extra-args: --timeout 600s
validate-maintainers: false

helm-unittest — Unit Tests for Templates

# Install plugin
helm plugin install https://github.com/helm-unittest/helm-unittest

# Run tests
helm unittest ./my-chart

# tests/deployment_test.yaml
suite: Deployment tests
templates:
  - deployment.yaml
tests:
  - it: should create a deployment with correct replicas
    set:
      replicaCount: 3
    asserts:
      - isKind:
          of: Deployment
      - equal:
          path: spec.replicas
          value: 3

  - it: should set resource limits
    set:
      resources.limits.cpu: "500m"
      resources.limits.memory: "256Mi"
    asserts:
      - equal:
          path: spec.template.spec.containers[0].resources.limits.cpu
          value: "500m"

  - it: should not create PDB when disabled
    set:
      podDisruptionBudget.enabled: false
    asserts:
      - hasDocuments:
          count: 0
        template: pdb.yaml

  - it: should add GPU tolerations when GPU enabled
    set:
      gpu.enabled: true
    asserts:
      - contains:
          path: spec.template.spec.tolerations
          content:
            key: nvidia.com/gpu
            operator: Exists
            effect: NoSchedule

  - it: should fail without required values
    set:
      image.repository: ""
    asserts:
      - failedTemplate: {}

GitHub Actions CI Pipeline

# .github/workflows/helm-test.yaml
name: Helm Chart CI

on:
  pull_request:
    paths:
      - 'charts/**'

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - uses: azure/setup-helm@v4

      - name: Helm lint
        run: |
          for chart in charts/*/; do
            helm lint "$chart" --strict
            helm lint "$chart" --values "$chart/values-production.yaml" --strict || true
          done

  unit-test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: azure/setup-helm@v4

      - name: Install helm-unittest
        run: helm plugin install https://github.com/helm-unittest/helm-unittest

      - name: Run unit tests
        run: |
          for chart in charts/*/; do
            helm unittest "$chart"
          done

  integration-test:
    runs-on: ubuntu-latest
    needs: [lint, unit-test]
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - uses: azure/setup-helm@v4

      - name: Create kind cluster
        uses: helm/kind-action@v1

      - name: Install chart-testing
        uses: helm/chart-testing-action@v2

      - name: Run chart-testing
        run: ct install --config ct.yaml

  release:
    runs-on: ubuntu-latest
    needs: [integration-test]
    if: github.ref == 'refs/heads/main'
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Configure Git
        run: |
          git config user.name "helm-bot"
          git config user.email "helm-bot@example.com"

      - name: Publish to ChartMuseum / OCI
        run: |
          helm package charts/my-chart
          helm push my-chart-*.tgz oci://ghcr.io/myorg/charts

Schema Validation

// charts/my-chart/values.schema.json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "required": ["image", "replicaCount"],
  "properties": {
    "replicaCount": {
      "type": "integer",
      "minimum": 1,
      "maximum": 100
    },
    "image": {
      "type": "object",
      "required": ["repository", "tag"],
      "properties": {
        "repository": { "type": "string", "minLength": 1 },
        "tag": { "type": "string", "minLength": 1 }
      }
    }
  }
}

graph LR
    A[PR opened] --> B[helm lint --strict]
    B --> C[helm-unittest]
    C --> D[ct lint]
    D --> E[kind cluster]
    E --> F[ct install]
    F --> G{Tests pass?}
    G -->|Yes| H[Merge + helm push OCI]
    G -->|No| I[Block PR]

Common Issues

Best Practices

• Lint + unit test on every PR — fast feedback (<30 seconds)
• Integration test on merge — slower but catches runtime issues
• Schema validate values.yaml — catch misconfigurations early
• Test multiple value combinations — production, staging, minimal
• Version bump in CI — auto-increment chart version on release

Key Takeaways

• helm-unittest catches template logic bugs without a cluster
• chart-testing (ct) validates full install/upgrade cycles on kind
• GitHub Actions provides free CI for open-source Helm charts
• Schema validation prevents invalid values before deployment
• Test pyramid: lint (fast) → unit (medium) → integration (slow)