Wait for kube api during init (#440)

* kubernetes: wait for KubeAPI to be reachable

bootstrapper/internal/kubernetes/kubeWaiter/waiter_test.go

@@ -0,0 +1,60 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package kubewaiter
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.uber.org/goleak"
+	corev1 "k8s.io/api/core/v1"
+)
+
+func TestMain(m *testing.M) {
+	goleak.VerifyTestMain(m)
+}
+
+func TestCloudKubeAPIWaiter(t *testing.T) {
+	testCases := map[string]struct {
+		kubeClient KubernetesClient
+		wantErr    bool
+	}{
+		"success": {
+			kubeClient: &stubKubernetesClient{},
+		},
+		"error": {
+			kubeClient: &stubKubernetesClient{listAllNamespacesErr: errors.New("error")},
+			wantErr:    true,
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			require := require.New(t)
+
+			waiter := &CloudKubeAPIWaiter{}
+			ctx, cancel := context.WithTimeout(context.Background(), 0)
+			defer cancel()
+			err := waiter.Wait(ctx, tc.kubeClient)
+			if tc.wantErr {
+				require.Error(err)
+			} else {
+				require.NoError(err)
+			}
+		})
+	}
+}
+
+type stubKubernetesClient struct {
+	listAllNamespacesErr error
+}
+
+func (c *stubKubernetesClient) ListAllNamespaces(ctx context.Context) (*corev1.NamespaceList, error) {
+	return nil, c.listAllNamespacesErr
+}