How do you implement Helm chart testing with Terratest and other tools?

Chart testing ensures reliability before production deployment. Multiple tools provide different testing approaches.

1. Helm unittest (native Helm testing): # tests/deployment_test.yaml suite: test deployment templates: - deployment.yaml tests: - it: should create deployment with proper labels asserts: - isKind: of: Deployment - hasDocuments: count: 1 - equal: path: metadata.labels.app value: myapp - equal: path: spec.replicas value: 3 - matchRegex: path: spec.template.spec.containers[0].image pattern: "myapp:.*" set: replicaCount: 3 image.tag: latest Run: helm unittest ./mychart

2. Terratest (Go-based real cluster testing): package test import ( "testing" "github.com/gruntwork-io/terratest/modules/helm" "github.com/gruntwork-io/terratest/modules/k8s" ) func TestHelmChart(t *testing.T) { helmOptions := &helm.Options{ SetValues: map[string]string{ "replicaCount": "3", "image.tag": "test", }, } releaseName := "test-myapp" namespaceName := "test-namespace" // Install chart helm.Install(t, helmOptions, "./mychart", releaseName) // Verify deployment deployment := k8s.GetDeployment(t, kubectlOptions, releaseName) assert.Equal(t, int32(3), *deployment.Spec.Replicas) // Test connectivity pod := k8s.GetPod(t, kubectlOptions, releaseName) tunnel := k8s.NewTunnel(t, kubectlOptions, k8s.ResourceTypePod, pod.Name, 8080, 80) tunnel.ForwardPort(t) resp, err := http.Get("http://localhost:8080/health") assert.NoError(t, err) assert.Equal(t, 200, resp.StatusCode) // Cleanup helm.Delete(t, helmOptions, releaseName, true) }

3. Chart Testing (ct) tool: # ct.yaml config target-branch: main validate-maintainers: false chart-dirs: - charts helm-extra-args: --timeout 300s check-version-increment: true # Run tests ct lint --config ct.yaml ct install --config ct.yaml --namespace ct-test

4. Goss integration for validation: # goss.yaml http: http://myapp-service:8080/health: status: 200 body: ["OK"] timeout: 1000 command: kubectl get pods -l app=myapp: exit-status: 0 stdout: - Running

5. CI/CD testing pipeline (GitHub Actions): name: Test Helm Charts on: [pull_request] jobs: test: runs-on: ubuntu-latest steps: - uses: actions/checkout@v3 - uses: helm/kind-action@v1 - name: Run chart tests run: | helm unittest ./charts/*/ ct install --config ct.yaml