Adding Unit Test for util/pkg/exec/exec.go

Signed-off-by: Nguyen Hai Truong <truongnh@vn.fujitsu.com>

util/pkg/exec/BUILD.bazel

@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "go_default_library",
@@ -6,3 +6,9 @@ go_library(
     importpath = "k8s.io/kops/util/pkg/exec",
     visibility = ["//visibility:public"],
 )
+
+go_test(
+    name = "go_default_test",
+    srcs = ["exec_test.go"],
+    embed = [":go_default_library"],
+)

util/pkg/exec/exec_test.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2020 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 exec
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestWithTee(t *testing.T) {
+	tests := []struct {
+		cmd      string
+		args     []string
+		logfile  string
+		expected []string
+	}{
+		{
+			cmd:     "ls",
+			args:    []string{"-l", "-a"},
+			logfile: "/var/log/ls.log",
+			expected: []string{
+				"/bin/sh",
+				"-c",
+				"mkfifo /tmp/pipe; (tee -a /var/log/ls.log < /tmp/pipe & ) ; exec ls -l -a > /tmp/pipe 2>&1",
+			},
+		},
+	}
+
+	for _, test := range tests {
+		result := WithTee(test.cmd, test.args, test.logfile)
+		if !reflect.DeepEqual(result, test.expected) {
+			t.Errorf("Actual result %v, expected %v", result, test.expected)
+		}
+	}
+}