chore(helm): add unit tests for helm chart (#6557)

This PR adds a minimum set of Helm tests for the Helm chart.
It's heavily based on the approach in [1], but uses a golden-files-based approach instead.
It also runs helm template directly instead of importing the entire Kubernetes API.
Golden files can be updated by running go test ./helm/tests -update or by running make update-golden-files.

[1] https://github.com/coder/enterprise-helm

Fixes #6552

helm/tests/testdata/default_values.golden

@@ -0,0 +1,161 @@
+---
+# Source: coder/templates/coder.yaml
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: "coder"
+  annotations: 
+    {}
+  labels:
+    helm.sh/chart: coder-0.1.0
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+    app.kubernetes.io/part-of: coder
+    app.kubernetes.io/version: "0.1.0"
+    app.kubernetes.io/managed-by: Helm
+---
+# Source: coder/templates/rbac.yaml
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: coder-workspace-perms
+rules:
+  - apiGroups: [""]
+    resources: ["pods"]
+    verbs: ["*"]
+  - apiGroups: [""]
+    resources: ["persistentvolumeclaims"]
+    verbs: ["*"]
+---
+# Source: coder/templates/rbac.yaml
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: "coder"
+subjects:
+  - kind: ServiceAccount
+    name: "coder"
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: coder-workspace-perms
+---
+# Source: coder/templates/service.yaml
+apiVersion: v1
+kind: Service
+metadata:
+  name: coder
+  labels:
+    helm.sh/chart: coder-0.1.0
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+    app.kubernetes.io/part-of: coder
+    app.kubernetes.io/version: "0.1.0"
+    app.kubernetes.io/managed-by: Helm
+  annotations:
+    {}
+spec:
+  type: LoadBalancer
+  sessionAffinity: ClientIP
+  ports:
+    - name: "http"
+      port: 80
+      targetPort: "http"
+      protocol: TCP
+  externalTrafficPolicy: "Cluster"
+  selector:
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+---
+# Source: coder/templates/coder.yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: coder
+  labels:
+    helm.sh/chart: coder-0.1.0
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+    app.kubernetes.io/part-of: coder
+    app.kubernetes.io/version: "0.1.0"
+    app.kubernetes.io/managed-by: Helm
+  annotations: 
+    {}
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: coder
+      app.kubernetes.io/instance: release-name
+  template:
+    metadata:
+      labels:
+        helm.sh/chart: coder-0.1.0
+        app.kubernetes.io/name: coder
+        app.kubernetes.io/instance: release-name
+        app.kubernetes.io/part-of: coder
+        app.kubernetes.io/version: "0.1.0"
+        app.kubernetes.io/managed-by: Helm
+    spec:
+      serviceAccountName: "coder"
+      restartPolicy: Always
+      terminationGracePeriodSeconds: 60
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+          - podAffinityTerm:
+              labelSelector:
+                matchExpressions:
+                - key: app.kubernetes.io/instance
+                  operator: In
+                  values:
+                  - coder
+              topologyKey: kubernetes.io/hostname
+            weight: 1
+      containers:
+        - name: coder
+          image: "ghcr.io/coder/coder:latest"
+          imagePullPolicy: IfNotPresent
+          resources:
+            {}
+          env:
+            - name: CODER_HTTP_ADDRESS
+              value: "0.0.0.0:8080"
+            - name: CODER_PROMETHEUS_ADDRESS
+              value: "0.0.0.0:2112"
+            # Set the default access URL so a `helm apply` works by default.
+            # See: https://github.com/coder/coder/issues/5024
+            - name: CODER_ACCESS_URL
+              value: "http://coder.default.svc.cluster.local"
+            # Used for inter-pod communication with high-availability.
+            - name: KUBE_POD_IP
+              valueFrom:
+                fieldRef:
+                  fieldPath: status.podIP
+            - name: CODER_DERP_SERVER_RELAY_URL
+              value: "http://$(KUBE_POD_IP):8080"
+            
+          ports:
+            - name: "http"
+              containerPort: 8080
+              protocol: TCP
+          securityContext: 
+            allowPrivilegeEscalation: false
+            readOnlyRootFilesystem: null
+            runAsGroup: 1000
+            runAsNonRoot: true
+            runAsUser: 1000
+            seccompProfile:
+              type: RuntimeDefault
+          readinessProbe:
+            httpGet:
+              path: /api/v2/buildinfo
+              port: "http"
+              scheme: "HTTP"
+          livenessProbe:
+            httpGet:
+              path: /api/v2/buildinfo
+              port: "http"
+              scheme: "HTTP"
+          volumeMounts: []
+      volumes: []

helm/tests/testdata/default_values.yaml

@@ -0,0 +1,3 @@
+coder:
+  image:
+    tag: latest

helm/tests/testdata/tls.golden

@@ -0,0 +1,183 @@
+---
+# Source: coder/templates/coder.yaml
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: "coder"
+  annotations: 
+    {}
+  labels:
+    helm.sh/chart: coder-0.1.0
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+    app.kubernetes.io/part-of: coder
+    app.kubernetes.io/version: "0.1.0"
+    app.kubernetes.io/managed-by: Helm
+---
+# Source: coder/templates/rbac.yaml
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: coder-workspace-perms
+rules:
+  - apiGroups: [""]
+    resources: ["pods"]
+    verbs: ["*"]
+  - apiGroups: [""]
+    resources: ["persistentvolumeclaims"]
+    verbs: ["*"]
+---
+# Source: coder/templates/rbac.yaml
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: "coder"
+subjects:
+  - kind: ServiceAccount
+    name: "coder"
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: coder-workspace-perms
+---
+# Source: coder/templates/service.yaml
+apiVersion: v1
+kind: Service
+metadata:
+  name: coder
+  labels:
+    helm.sh/chart: coder-0.1.0
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+    app.kubernetes.io/part-of: coder
+    app.kubernetes.io/version: "0.1.0"
+    app.kubernetes.io/managed-by: Helm
+  annotations:
+    {}
+spec:
+  type: LoadBalancer
+  sessionAffinity: ClientIP
+  ports:
+    - name: "http"
+      port: 80
+      targetPort: "http"
+      protocol: TCP
+    - name: "https"
+      port: 443
+      targetPort: "https"
+      protocol: TCP
+  externalTrafficPolicy: "Cluster"
+  selector:
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+---
+# Source: coder/templates/coder.yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: coder
+  labels:
+    helm.sh/chart: coder-0.1.0
+    app.kubernetes.io/name: coder
+    app.kubernetes.io/instance: release-name
+    app.kubernetes.io/part-of: coder
+    app.kubernetes.io/version: "0.1.0"
+    app.kubernetes.io/managed-by: Helm
+  annotations: 
+    {}
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: coder
+      app.kubernetes.io/instance: release-name
+  template:
+    metadata:
+      labels:
+        helm.sh/chart: coder-0.1.0
+        app.kubernetes.io/name: coder
+        app.kubernetes.io/instance: release-name
+        app.kubernetes.io/part-of: coder
+        app.kubernetes.io/version: "0.1.0"
+        app.kubernetes.io/managed-by: Helm
+    spec:
+      serviceAccountName: "coder"
+      restartPolicy: Always
+      terminationGracePeriodSeconds: 60
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+          - podAffinityTerm:
+              labelSelector:
+                matchExpressions:
+                - key: app.kubernetes.io/instance
+                  operator: In
+                  values:
+                  - coder
+              topologyKey: kubernetes.io/hostname
+            weight: 1
+      containers:
+        - name: coder
+          image: "ghcr.io/coder/coder:latest"
+          imagePullPolicy: IfNotPresent
+          resources:
+            {}
+          env:
+            - name: CODER_HTTP_ADDRESS
+              value: "0.0.0.0:8080"
+            - name: CODER_PROMETHEUS_ADDRESS
+              value: "0.0.0.0:2112"
+            # Set the default access URL so a `helm apply` works by default.
+            # See: https://github.com/coder/coder/issues/5024
+            - name: CODER_ACCESS_URL
+              value: "https://coder.default.svc.cluster.local"
+            # Used for inter-pod communication with high-availability.
+            - name: KUBE_POD_IP
+              valueFrom:
+                fieldRef:
+                  fieldPath: status.podIP
+            - name: CODER_DERP_SERVER_RELAY_URL
+              value: "http://$(KUBE_POD_IP):8080"
+            
+            - name: CODER_TLS_ENABLE
+              value: "true"
+            - name: CODER_TLS_ADDRESS
+              value: "0.0.0.0:8443"
+            - name: CODER_TLS_CERT_FILE
+              value: "/etc/ssl/certs/coder/coder-tls/tls.crt"
+            - name: CODER_TLS_KEY_FILE
+              value: "/etc/ssl/certs/coder/coder-tls/tls.key"
+          ports:
+            - name: "http"
+              containerPort: 8080
+              protocol: TCP
+            - name: "https"
+              containerPort: 8443
+              protocol: TCP
+          securityContext: 
+            allowPrivilegeEscalation: false
+            readOnlyRootFilesystem: null
+            runAsGroup: 1000
+            runAsNonRoot: true
+            runAsUser: 1000
+            seccompProfile:
+              type: RuntimeDefault
+          readinessProbe:
+            httpGet:
+              path: /api/v2/buildinfo
+              port: "http"
+              scheme: "HTTP"
+          livenessProbe:
+            httpGet:
+              path: /api/v2/buildinfo
+              port: "http"
+              scheme: "HTTP"
+          volumeMounts:
+          - name: "tls-coder-tls"
+            mountPath: "/etc/ssl/certs/coder/coder-tls"
+            readOnly: true
+          
+      volumes:
+      - name: "tls-coder-tls"
+        secret:
+          secretName: "coder-tls"

helm/tests/testdata/tls.yaml

@@ -0,0 +1,6 @@
+coder:
+  image:
+    tag: latest
+  tls:
+    secretNames:
+      - coder-tls