diff --git a/cmd/root_cmd_test.go b/cmd/root_cmd_test.go
new file mode 100755
index 0000000..1ab6169
--- /dev/null
+++ b/cmd/root_cmd_test.go
@@ -0,0 +1,100 @@
+package cmd
+
+import (
+	"bytes"
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/matryer/is"
+	"github.com/spf13/cobra"
+)
+
+func TestRootCmd(t *testing.T) {
+	is := is.New(t)
+
+	// root := &cobra.Command{Use: "root"}
+	// cmd.RootCmdFlags(root)
+
+	err := rootCmd.Execute()
+
+	is.NoErr(err)
+}
+
+func execute(t *testing.T, c *cobra.Command, args ...string) (string, error) {
+	t.Helper()
+
+	buf := new(bytes.Buffer)
+	c.SetOut(buf)
+	c.SetErr(buf)
+	c.SetArgs(args)
+
+	err := c.Execute()
+	return strings.TrimSpace(buf.String()), err
+}
+
+func TestSubCmd(t *testing.T) {
+	is := is.New(t)
+
+	testcases := []struct {
+		args      []string
+		out_check bool
+		err       error
+		out       string
+	}{
+		{[]string{}, false, nil, ""},
+		{[]string{"wrong"}, true, errors.New("unknown command \"wrong\" for \"tks\""), ""},
+		// {[]string{"wrong", "cmd"}, true, errors.New("unknown command \"wrong\" for \"tks\""), ""},
+
+		{[]string{"completion"}, false, nil, ""},
+		{[]string{"completion", "bash"}, false, nil, ""},
+		{[]string{"completion", "fish"}, false, nil, ""},
+		{[]string{"completion", "powershell"}, false, nil, ""},
+		{[]string{"completion", "zsh"}, false, nil, ""},
+
+		{[]string{"--config"}, true, errors.New("flag needs an argument: --config"), ""},
+		{[]string{"-t"}, false, nil, ""},
+
+		{[]string{"cluster"}, true, nil, ""},
+		{[]string{"cluster", "wrong"}, true, nil, ""},
+		{[]string{"cluster", "create"}, true, errors.New("required flag(s) \"contract-id\", \"csp-id\" not set"), ""},
+		{[]string{"cluster", "create", "--config"}, true, errors.New("flag needs an argument: --config"), ""},
+		{[]string{"cluster", "create", "--config", "xx"}, true, errors.New("required flag(s) \"contract-id\", \"csp-id\" not set"), ""},
+		{[]string{"cluster", "create", "-h"}, false, nil, "Create a TACO Cluster to AWS."},
+		{[]string{"cluster", "create", "--contract-id"}, true, errors.New("flag needs an argument: --contract-id"), ""},
+		{[]string{"cluster", "create", "--contract-id", "1234"}, false, nil, ""},
+		{[]string{"cluster", "create", "--csp-id"}, false, errors.New("flag needs an argument: --csp-id"), ""},
+		{[]string{"cluster", "create", "--contract-id", "--csp-id"}, false, nil, ""},
+		{[]string{"cluster", "create", "--contract-id", "abcd-efg", "--csp-id"}, true, errors.New("flag needs an argument: --csp-id"), ""},
+		{[]string{"cluster", "create", "--contract-id", "--csp-id", "2345234", "hihi"}, false, nil, "Create a TACO Cluster to AWS"},
+		{[]string{"cluster", "create", "--contract-id", "--csp-id", "2345234", "hihi", "--config"}, true, errors.New("flag needs an argument: --config"), ""},
+		{[]string{"cluster", "create", "--contract-id", "abcd-efg", "--csp-id", "2345234", "hihi"}, false, nil, "Create a TACO Cluster to AWS"},
+
+		{[]string{"cluster", "list"}, true, nil, ""},
+		{[]string{"cluster", "list", "-h"}, false, nil, "A longer description that spans multiple lines and likely contains examples"},
+		{[]string{"cluster", "list", "--config", "xx"}, false, nil, "A longer description that spans multiple lines and likely contains examples"},
+		{[]string{"cluster", "list", "--config"}, true, errors.New("flag needs an argument: --config"), ""},
+
+		{[]string{"endpoint"}, true, nil, ""},
+		{[]string{"endpoint", "register"}, true, nil, ""},
+		{[]string{"endpoint", "wrong"}, true, nil, ""},
+		{[]string{"service"}, true, nil, ""},
+
+		{[]string{"help"}, false, nil, ""},
+		{[]string{"-t"}, false, nil, ""},
+		{[]string{"-h"}, false, nil, ""},
+
+		{[]string{"register"}, true, errors.New("unknown command \"register\" for \"tks\""), "Run 'tks --help' for usage."},
+		{[]string{"abcd"}, true, errors.New("unknown command \"abcd\" for \"tks\""), ""},
+	}
+
+	for _, tc := range testcases {
+		out, err := execute(t, rootCmd, tc.args...)
+
+		is.Equal(tc.err, err)
+
+		if tc.err == nil && tc.out_check {
+			is.Equal(tc.out, out)
+		}
+	}
+}
diff --git a/go.mod b/go.mod
index 5896a5f..b8eeff3 100644
--- a/go.mod
+++ b/go.mod
@@ -5,10 +5,12 @@ go 1.16
 require (
 	github.com/golang/mock v1.6.0
 	github.com/kr/text v0.2.0 // indirect
+	github.com/matryer/is v1.4.0
 	github.com/openinfradev/tks-contract v0.1.1-0.20210928021110-fe2b666327cc
 	github.com/openinfradev/tks-proto v0.0.6-0.20211015003551-ed8f9541f40d
 	github.com/spf13/cobra v1.2.1
 	github.com/spf13/viper v1.9.0
+	github.com/stretchr/testify v1.7.0
 	golang.org/x/net v0.0.0-20211020060615-d418f374d309 // indirect
 	golang.org/x/sys v0.0.0-20211023085530-d6a326fbbf70 // indirect
 	google.golang.org/genproto v0.0.0-20211021150943-2b146023228c // indirect
diff --git a/go.sum b/go.sum
index 4a42e84..e655226 100644
--- a/go.sum
+++ b/go.sum
@@ -365,6 +365,8 @@ github.com/lightstep/lightstep-tracer-go v0.18.1/go.mod h1:jlF1pusYV4pidLvZ+XD0U
 github.com/lyft/protoc-gen-validate v0.0.13/go.mod h1:XbGvPuh87YZc5TdIa2/I4pLk0QoUACkjt2znoq26NVQ=
 github.com/magiconair/properties v1.8.5 h1:b6kJs+EmPFMYGkow9GiUyCyOvIwYetYJ3fSaWak/Gls=
 github.com/magiconair/properties v1.8.5/go.mod h1:y3VJvCyxH9uVvJTWEGAELF3aiYNyPKd5NZ3oSwXrF60=
+github.com/matryer/is v1.4.0 h1:sosSmIWwkYITGrxZ25ULNDeKiMNzFSr4V/eqBQP0PeE=
+github.com/matryer/is v1.4.0/go.mod h1:8I/i5uYgLzgsgEloJE1U6xx5HkBQpAZvepWuujKwMRU=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-colorable v0.1.1/go.mod h1:FuOcm+DKB9mbwrcAfNl7/TZVBZ6rcnceauSikq3lYCQ=
 github.com/mattn/go-colorable v0.1.2/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=