Add envtest

I know it's not an impressive test. It just brings up a node, and
makes sure it registers. Let's do more in the future.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>

internal/test/util/provider.go

@@ -0,0 +1 @@
+package util

internal/test/vk_envtest/env_test.go

@@ -0,0 +1,106 @@
+package e2e_test
+
+import (
+	"context"
+	"flag"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/bombsimon/logrusr"
+	"github.com/sirupsen/logrus"
+	"github.com/virtual-kubelet/virtual-kubelet/log"
+	logruslogger "github.com/virtual-kubelet/virtual-kubelet/log/logrus"
+	"github.com/virtual-kubelet/virtual-kubelet/node"
+	"gotest.tools/assert"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+	klogv1 "k8s.io/klog"
+	klogv2 "k8s.io/klog/v2"
+	"sigs.k8s.io/controller-runtime/pkg/envtest"
+)
+
+var enableEnvTest = flag.Bool("envtest", false, "Enable envtest based tests")
+
+func TestMain(m *testing.M) {
+	flagset := flag.NewFlagSet("klog", flag.PanicOnError)
+	klogv1.InitFlags(flagset)
+	flagset.VisitAll(func(f *flag.Flag) {
+		flag.Var(f.Value, "klog."+f.Name, f.Usage)
+	})
+	flag.Parse()
+	os.Exit(m.Run())
+}
+
+func TestEnvtest(t *testing.T) {
+	if !*enableEnvTest || os.Getenv("VK_ENVTEST") != "" {
+		t.Skip("test only runs when -envtest is passed or if VK_ENVTEST is set to a non-empty value")
+	}
+	env := &envtest.Environment{}
+	_, err := env.Start()
+	assert.NilError(t, err)
+	defer func() {
+		assert.NilError(t, env.Stop())
+	}()
+
+	t.Log("Env test environment ready")
+	t.Run("E2ERun", func(t *testing.T) {
+		testNodeE2ERun(t, env)
+	})
+}
+
+func testNodeE2ERun(t *testing.T, env *envtest.Environment) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	sl := logrus.StandardLogger()
+	sl.SetLevel(logrus.DebugLevel)
+	klogv2.SetLogger(logrusr.NewLogger(sl))
+	newLogger := logruslogger.FromLogrus(logrus.NewEntry(sl))
+	ctx = log.WithLogger(ctx, newLogger)
+
+	clientset, err := kubernetes.NewForConfig(env.Config)
+	assert.NilError(t, err)
+	nodes := clientset.CoreV1().Nodes()
+	_, err = clientset.CoreV1().Nodes().List(ctx, metav1.ListOptions{})
+	assert.NilError(t, err)
+
+	testProvider := node.NewNaiveNodeProvider()
+
+	testNode := &corev1.Node{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "e2e-envtest",
+		},
+	}
+
+	testNodeCopy := testNode.DeepCopy()
+
+	node, err := node.NewNodeController(testProvider, testNode, nodes)
+	assert.NilError(t, err)
+
+	chErr := make(chan error, 1)
+	go func() {
+		chErr <- node.Run(ctx)
+	}()
+
+	<-node.Ready()
+
+	now := time.Now()
+	for time.Since(now) < time.Minute*5 {
+		n, err := nodes.Get(ctx, testNodeCopy.Name, metav1.GetOptions{})
+		if errors.IsNotFound(err) {
+			continue
+		}
+		if err == nil {
+			t.Log(n)
+			cancel()
+			err := <-chErr
+			assert.NilError(t, err)
+			return
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	t.Fatal("Node never found")
+}