kubeadm: add command-line integration test to ensure that the supported etcd version is always available for the stable Kubernetes version

cmd/kubeadm/test/cmd/config_test.go

@@ -0,0 +1,57 @@
+/*
+Copyright 2023 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 kubeadm
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestCmdConfigImagesList(t *testing.T) {
+	var tests = []struct {
+		name     string
+		args     string
+		expected bool
+	}{
+		{
+			name:     "valid: latest stable Kubernetes version should not throw the warning that a supported etcd version cannot be found",
+			args:     "--kubernetes-version=stable-1",
+			expected: false,
+		},
+	}
+
+	kubeadmPath := getKubeadmPath()
+	for _, rt := range tests {
+		t.Run(rt.name, func(t *testing.T) {
+			_, stderr, _, err := RunCmd(kubeadmPath, "config", "images", "list", "--v=1", rt.args)
+			if err != nil {
+				t.Fatalf("failed to run 'kubeadm config images list --v=1 %s', err: %v", rt.args, err)
+			}
+			actual := strings.Contains(stderr, "could not find officially supported version of etcd")
+			if actual != rt.expected {
+				t.Errorf(
+					"failed CmdConfigImagesList running 'kubeadm config images list --v=1 %s' with stderr output:\n%v\n\t  expected: %t\n\t  actual: %t\n\n"+
+						"FYI: This usually indicates that the 'SupportedEtcdVersion' map defined in 'cmd/kubeadm/app/constants/constants.go' needs to be updated.\n",
+					rt.args,
+					stderr,
+					rt.expected,
+					actual,
+				)
+			}
+		})
+	}
+}