test: add example test

examples/kubernetes-kustomize-example/README.md

@@ -0,0 +1,36 @@
+# Kubernetes Kustomize Example
+
+This folder contains a minimal Kubernetes resource config file to demonstrate how you can use Terratest to write
+automated tests for Kubernetes.
+
+This resource file deploys an nginx container as a single pod deployment with a node port service attached to it.
+
+See the corresponding terratest code for an example of how to test this resource config:
+- [kubernetes_kustomize_example_test.go](../../test/kubernetes_kustomize_example_test.go)
+
+
+## Deploying the Kubernetes resource
+
+1. Setup a Kubernetes cluster. We recommend using a local version:
+    - [minikube](https://github.com/kubernetes/minikube)
+    - [Kubernetes on Docker For Mac](https://docs.docker.com/docker-for-mac/kubernetes/)
+    - [Kubernetes on Docker For Windows](https://docs.docker.com/docker-for-windows/kubernetes/)
+
+1. Install and setup [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/) to talk to the deployed
+   Kubernetes cluster.
+1. Run `kubectl apply -k .`
+
+
+## Running automated tests against this Kubernetes deployment
+
+1. Setup a Kubernetes cluster. We recommend using a local version:
+    - [minikube](https://github.com/kubernetes/minikube)
+    - [Kubernetes on Docker For Mac](https://docs.docker.com/docker-for-mac/kubernetes/)
+    - [Kubernetes on Docker For Windows](https://docs.docker.com/docker-for-windows/kubernetes/)
+
+1. Install and setup [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/) to talk to the deployed
+   Kubernetes cluster.
+1. Install [Golang](https://golang.org/) and make sure this code is checked out into your `GOPATH`.
+1. `cd test`
+1. `dep ensure`
+1. `go test -v -tags kubernetes -run TestKubernetesKustomizeExample`

examples/kubernetes-kustomize-example/deployment.yaml

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+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx-deployment
+spec:
+  selector:
+    matchLabels:
+      app: nginx
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.15.7
+        ports:
+        - containerPort: 80

examples/kubernetes-kustomize-example/kustomization.yaml

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+resources:
+- ./deployment.yaml
+- ./service.yaml

examples/kubernetes-kustomize-example/service.yaml

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+---
+kind: Service
+apiVersion: v1
+metadata:
+  name: nginx-service
+spec:
+  selector:
+    app: nginx
+  ports:
+    - protocol: TCP
+      targetPort: 80
+      port: 1080
+  type: NodePort

test/kubernetes_kustomize_example_test.go

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+//go:build kubeall || kubernetes
+// +build kubeall kubernetes
+
+// NOTE: we have build tags to differentiate kubernetes tests from non-kubernetes tests. This is done because minikube
+// is heavy and can interfere with docker related tests in terratest. Specifically, many of the tests start to fail with
+// `connection refused` errors from `minikube`. To avoid overloading the system, we run the kubernetes tests and helm
+// tests separately from the others. This may not be necessary if you have a sufficiently powerful machine.  We
+// recommend at least 4 cores and 16GB of RAM if you want to run all the tests together.
+
+package test
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/gruntwork-io/terratest/modules/k8s"
+	"github.com/gruntwork-io/terratest/modules/random"
+)
+
+// An example of how to test the Kubernetes resource config in examples/kubernetes-kustomize-example using Terratest.
+func TestKubernetesKustomizeExample(t *testing.T) {
+	t.Parallel()
+
+	// website::tag::1::Path to the Kubernetes resource config we will test
+	kubeResourcePath, err := filepath.Abs("../examples/kubernetes-kustomize-example/")
+	require.NoError(t, err)
+
+	// To ensure we can reuse the resource config on the same cluster to test different scenarios, we setup a unique
+	// namespace for the resources for this test.
+	// Note that namespaces must be lowercase.
+	namespaceName := fmt.Sprintf("kubernetes-kustomize-example-%s", strings.ToLower(random.UniqueId()))
+
+	// website::tag::2::Setup the kubectl config and context.
+	// Here we choose to use the defaults, which is:
+	// - HOME/.kube/config for the kubectl config file
+	// - Current context of the kubectl config file
+	// - Random namespace
+	options := k8s.NewKubectlOptions("", "", namespaceName)
+
+	k8s.CreateNamespace(t, options, namespaceName)
+	// website::tag::5::Make sure to delete the namespace at the end of the test
+	defer k8s.DeleteNamespace(t, options, namespaceName)
+
+	// website::tag::6::At the end of the test, run `kubectl delete -f RESOURCE_CONFIG` to clean up any resources that were created.
+	defer k8s.KubectlDeleteFromKustomize(t, options, kubeResourcePath)
+
+	// website::tag::3::Apply kubectl with 'kubectl apply -f RESOURCE_CONFIG' command.
+	// This will run `kubectl apply -f RESOURCE_CONFIG` and fail the test if there are any errors
+	k8s.KubectlApplyFromKustomize(t, options, kubeResourcePath)
+
+	// website::tag::4::Check if NGINX service was deployed successfully.
+	// This will get the service resource and verify that it exists and was retrieved successfully. This function will
+	// fail the test if the there is an error retrieving the service resource from Kubernetes.
+	service := k8s.GetService(t, options, "nginx-service")
+	require.Equal(t, service.Name, "nginx-service")
+}