kubectl: add integration test for result reporting

This currently covers two cases:
- "kubectl list" (the regression from https://github.com/kubernetes/kubernetes/issues/107012)
- "kubectl get pods/no-such-pod" (no particular reason except that the output
should be deterministic)

In contrast to some other tests that check for strings inside the
output (run_deprecated_api_tests) or compare after
sorting (run_kubectl_version_tests), stdout, stderr and the return code must
match exactly.

This ensures that there is no extra, unexpected output and that the right
output stream is used.

test/cmd/legacy-script.sh

@@ -50,6 +50,7 @@ source "${KUBE_ROOT}/test/cmd/plugins.sh"
 source "${KUBE_ROOT}/test/cmd/proxy.sh"
 source "${KUBE_ROOT}/test/cmd/rbac.sh"
 source "${KUBE_ROOT}/test/cmd/request-timeout.sh"
+source "${KUBE_ROOT}/test/cmd/results.sh"
 source "${KUBE_ROOT}/test/cmd/run.sh"
 source "${KUBE_ROOT}/test/cmd/save-config.sh"
 source "${KUBE_ROOT}/test/cmd/storage.sh"
@@ -436,6 +437,12 @@ runTests() {
 
   record_command run_kubectl_version_tests
 
+  ############################
+  # Kubectl result reporting #
+  ############################
+
+  record_command run_kubectl_results_tests
+
   #######################
   # kubectl config set #
   #######################

test/cmd/results.sh

@@ -0,0 +1,58 @@
+#!/usr/bin/env bash
+
+# Copyright 2022 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.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+
+############################################################
+# Kubectl result reporting for different failure scenarios #
+############################################################
+run_kubectl_results_tests() {
+  set -o nounset
+  set -o errexit
+
+  kube::log::status "Testing kubectl result output"
+  TEMP="${KUBE_TEMP}"
+  rm -f "${TEMP}/empty"
+  touch "${TEMP}/empty"
+
+  set +o errexit
+  kubectl list >"${TEMP}/actual_stdout" 2>"${TEMP}/actual_stderr"
+  res=$?
+  set -o errexit
+  cat >"${TEMP}/expected_stderr" <<EOF
+error: unknown command "list" for "kubectl"
+
+Did you mean this?
+	get
+	wait
+EOF
+  kube::test::results::diff "${TEMP}/actual_stdout" "${TEMP}/actual_stderr" "$res" "${TEMP}/empty" "${TEMP}/expected_stderr" 1 "kubectl list"
+
+  set +o errexit
+  kubectl get pod/no-such-pod >"${TEMP}/actual_stdout" 2>"${TEMP}/actual_stderr"
+  res=$?
+  set -o errexit
+  cat >"${TEMP}/expected_stderr" <<EOF
+Error from server (NotFound): pods "no-such-pod" not found
+EOF
+  kube::test::results::diff "${TEMP}/actual_stdout" "${TEMP}/actual_stderr" "$res" "${TEMP}/empty" "${TEMP}/expected_stderr" 1 "kubectl get pod/no-such-pod"
+
+  set +o nounset
+  set +o errexit
+}