From ee02f5ddc42a67166c91e539fe98cc6541db668e Mon Sep 17 00:00:00 2001
From: Jack <jackfrancis@gmail.com>
Date: Mon, 27 Sep 2021 14:20:24 -0700
Subject: [PATCH] RunCordonOrUncordon error if drainer has nil Ctx or Client

---
 .../src/k8s.io/kubectl/pkg/drain/default.go   |  6 ++
 .../k8s.io/kubectl/pkg/drain/default_test.go  | 69 +++++++++++++++++++
 2 files changed, 75 insertions(+)
 create mode 100644 staging/src/k8s.io/kubectl/pkg/drain/default_test.go

diff --git a/staging/src/k8s.io/kubectl/pkg/drain/default.go b/staging/src/k8s.io/kubectl/pkg/drain/default.go
index 43f5dc42ca0..20e1786b094 100644
--- a/staging/src/k8s.io/kubectl/pkg/drain/default.go
+++ b/staging/src/k8s.io/kubectl/pkg/drain/default.go
@@ -49,6 +49,12 @@ func RunNodeDrain(drainer *Helper, nodeName string) error {
 
 // RunCordonOrUncordon demonstrates the canonical way to cordon or uncordon a Node
 func RunCordonOrUncordon(drainer *Helper, node *corev1.Node, desired bool) error {
+	if drainer.Ctx == nil {
+		return fmt.Errorf("RunCordonOrUncordon error: drainer.Ctx can't be nil")
+	}
+	if drainer.Client == nil {
+		return fmt.Errorf("RunCordonOrUncordon error: drainer.Client can't be nil")
+	}
 	// TODO(justinsb): Ensure we have adequate e2e coverage of this function in library consumers
 	c := NewCordonHelper(node)
 
diff --git a/staging/src/k8s.io/kubectl/pkg/drain/default_test.go b/staging/src/k8s.io/kubectl/pkg/drain/default_test.go
new file mode 100644
index 00000000000..de7067197a0
--- /dev/null
+++ b/staging/src/k8s.io/kubectl/pkg/drain/default_test.go
@@ -0,0 +1,69 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package drain
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/client-go/kubernetes/fake"
+)
+
+func TestRunCordonOrUncordon(t *testing.T) {
+	nilContextError := fmt.Errorf("RunCordonOrUncordon error: drainer.Ctx can't be nil")
+	nilClientError := fmt.Errorf("RunCordonOrUncordon error: drainer.Client can't be nil")
+	tests := []struct {
+		description   string
+		drainer       *Helper
+		node          *corev1.Node
+		desired       bool
+		expectedError *error
+	}{
+		{
+			description: "nil context object",
+			drainer: &Helper{
+				Client: fake.NewSimpleClientset(),
+			},
+			desired:       true,
+			expectedError: &nilContextError,
+		},
+		{
+			description: "nil client object",
+			drainer: &Helper{
+				Ctx: context.TODO(),
+			},
+			desired:       true,
+			expectedError: &nilClientError,
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.description, func(t *testing.T) {
+			err := RunCordonOrUncordon(test.drainer, test.node, test.desired)
+			if test.expectedError == nil {
+				if err != nil {
+					t.Fatalf("%s: did not expect error, got err=%s", test.description, err.Error())
+				}
+			} else if err.Error() != (*test.expectedError).Error() {
+				t.Fatalf("%s: the error does not match expected error, got err=%s, expected err=%s", test.description, err, *test.expectedError)
+			}
+		})
+	}
+}