Updating server dependancies. (#7816)

1 files changed, 1316 insertions, 157 deletions

diff --git a/vendor/github.com/spf13/cobra/command_test.go b/vendor/github.com/spf13/cobra/command_test.go
index aa6658f85..edffc1501 100644
--- a/vendor/github.com/spf13/cobra/command_test.go
+++ b/vendor/github.com/spf13/cobra/command_test.go
@@ -11,27 +11,450 @@ import (
 	"github.com/spf13/pflag"
 )
 
-// test to ensure hidden commands run as intended
-func TestHiddenCommandExecutes(t *testing.T) {
+func emptyRun(*Command, []string) {}
+
+func executeCommand(root *Command, args ...string) (output string, err error) {
+	_, output, err = executeCommandC(root, args...)
+	return output, err
+}
+
+func executeCommandC(root *Command, args ...string) (c *Command, output string, err error) {
+	buf := new(bytes.Buffer)
+	root.SetOutput(buf)
+	root.SetArgs(args)
+
+	c, err = root.ExecuteC()
+
+	return c, buf.String(), err
+}
+
+func resetCommandLineFlagSet() {
+	pflag.CommandLine = pflag.NewFlagSet(os.Args[0], pflag.ExitOnError)
+}
+
+func checkStringContains(t *testing.T, got, expected string) {
+	if !strings.Contains(got, expected) {
+		t.Errorf("Expected to contain: \n %v\nGot:\n %v\n", expected, got)
+	}
+}
+
+func checkStringOmits(t *testing.T, got, expected string) {
+	if strings.Contains(got, expected) {
+		t.Errorf("Expected to not contain: \n %v\nGot: %v", expected, got)
+	}
+}
 
-	// ensure that outs does not already equal what the command will be setting it
-	// to, if it did this test would not actually be testing anything...
-	if outs == "hidden" {
-		t.Errorf("outs should NOT EQUAL hidden")
+func TestSingleCommand(t *testing.T) {
+	var rootCmdArgs []string
+	rootCmd := &Command{
+		Use:  "root",
+		Args: ExactArgs(2),
+		Run:  func(_ *Command, args []string) { rootCmdArgs = args },
 	}
+	aCmd := &Command{Use: "a", Args: NoArgs, Run: emptyRun}
+	bCmd := &Command{Use: "b", Args: NoArgs, Run: emptyRun}
+	rootCmd.AddCommand(aCmd, bCmd)
 
-	cmdHidden.Execute()
+	output, err := executeCommand(rootCmd, "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
 
-	// upon running the command, the value of outs should now be 'hidden'
-	if outs != "hidden" {
-		t.Errorf("Hidden command failed to run!")
+	got := strings.Join(rootCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("rootCmdArgs expected: %q, got: %q", expected, got)
 	}
 }
 
-// test to ensure hidden commands do not show up in usage/help text
-func TestHiddenCommandIsHidden(t *testing.T) {
-	if cmdHidden.IsAvailableCommand() {
-		t.Errorf("Hidden command found!")
+func TestChildCommand(t *testing.T) {
+	var child1CmdArgs []string
+	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
+	child1Cmd := &Command{
+		Use:  "child1",
+		Args: ExactArgs(2),
+		Run:  func(_ *Command, args []string) { child1CmdArgs = args },
+	}
+	child2Cmd := &Command{Use: "child2", Args: NoArgs, Run: emptyRun}
+	rootCmd.AddCommand(child1Cmd, child2Cmd)
+
+	output, err := executeCommand(rootCmd, "child1", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	got := strings.Join(child1CmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("child1CmdArgs expected: %q, got: %q", expected, got)
+	}
+}
+
+func TestCallCommandWithoutSubcommands(t *testing.T) {
+	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
+	_, err := executeCommand(rootCmd)
+	if err != nil {
+		t.Errorf("Calling command without subcommands should not have error: %v", err)
+	}
+}
+
+func TestRootExecuteUnknownCommand(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	rootCmd.AddCommand(&Command{Use: "child", Run: emptyRun})
+
+	output, _ := executeCommand(rootCmd, "unknown")
+
+	expected := "Error: unknown command \"unknown\" for \"root\"\nRun 'root --help' for usage.\n"
+
+	if output != expected {
+		t.Errorf("Expected:\n %q\nGot:\n %q\n", expected, output)
+	}
+}
+
+func TestSubcommandExecuteC(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+
+	c, output, err := executeCommandC(rootCmd, "child")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if c.Name() != "child" {
+		t.Errorf(`invalid command returned from ExecuteC: expected "child"', got %q`, c.Name())
+	}
+}
+
+func TestRootUnknownCommandSilenced(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	rootCmd.SilenceErrors = true
+	rootCmd.SilenceUsage = true
+	rootCmd.AddCommand(&Command{Use: "child", Run: emptyRun})
+
+	output, _ := executeCommand(rootCmd, "unknown")
+	if output != "" {
+		t.Errorf("Expected blank output, because of silenced usage.\nGot:\n %q\n", output)
+	}
+}
+
+func TestCommandAlias(t *testing.T) {
+	var timesCmdArgs []string
+	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
+	echoCmd := &Command{
+		Use:     "echo",
+		Aliases: []string{"say", "tell"},
+		Args:    NoArgs,
+		Run:     emptyRun,
+	}
+	timesCmd := &Command{
+		Use:  "times",
+		Args: ExactArgs(2),
+		Run:  func(_ *Command, args []string) { timesCmdArgs = args },
+	}
+	echoCmd.AddCommand(timesCmd)
+	rootCmd.AddCommand(echoCmd)
+
+	output, err := executeCommand(rootCmd, "tell", "times", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	got := strings.Join(timesCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("timesCmdArgs expected: %v, got: %v", expected, got)
+	}
+}
+
+func TestEnablePrefixMatching(t *testing.T) {
+	EnablePrefixMatching = true
+
+	var aCmdArgs []string
+	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
+	aCmd := &Command{
+		Use:  "aCmd",
+		Args: ExactArgs(2),
+		Run:  func(_ *Command, args []string) { aCmdArgs = args },
+	}
+	bCmd := &Command{Use: "bCmd", Args: NoArgs, Run: emptyRun}
+	rootCmd.AddCommand(aCmd, bCmd)
+
+	output, err := executeCommand(rootCmd, "a", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	got := strings.Join(aCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("aCmdArgs expected: %q, got: %q", expected, got)
+	}
+
+	EnablePrefixMatching = false
+}
+
+func TestAliasPrefixMatching(t *testing.T) {
+	EnablePrefixMatching = true
+
+	var timesCmdArgs []string
+	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
+	echoCmd := &Command{
+		Use:     "echo",
+		Aliases: []string{"say", "tell"},
+		Args:    NoArgs,
+		Run:     emptyRun,
+	}
+	timesCmd := &Command{
+		Use:  "times",
+		Args: ExactArgs(2),
+		Run:  func(_ *Command, args []string) { timesCmdArgs = args },
+	}
+	echoCmd.AddCommand(timesCmd)
+	rootCmd.AddCommand(echoCmd)
+
+	output, err := executeCommand(rootCmd, "sa", "times", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	got := strings.Join(timesCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("timesCmdArgs expected: %v, got: %v", expected, got)
+	}
+
+	EnablePrefixMatching = false
+}
+
+// TestChildSameName checks the correct behaviour of cobra in cases,
+// when an application with name "foo" and with subcommand "foo"
+// is executed with args "foo foo".
+func TestChildSameName(t *testing.T) {
+	var fooCmdArgs []string
+	rootCmd := &Command{Use: "foo", Args: NoArgs, Run: emptyRun}
+	fooCmd := &Command{
+		Use:  "foo",
+		Args: ExactArgs(2),
+		Run:  func(_ *Command, args []string) { fooCmdArgs = args },
+	}
+	barCmd := &Command{Use: "bar", Args: NoArgs, Run: emptyRun}
+	rootCmd.AddCommand(fooCmd, barCmd)
+
+	output, err := executeCommand(rootCmd, "foo", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	got := strings.Join(fooCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("fooCmdArgs expected: %v, got: %v", expected, got)
+	}
+}
+
+// TestGrandChildSameName checks the correct behaviour of cobra in cases,
+// when user has a root command and a grand child
+// with the same name.
+func TestGrandChildSameName(t *testing.T) {
+	var fooCmdArgs []string
+	rootCmd := &Command{Use: "foo", Args: NoArgs, Run: emptyRun}
+	barCmd := &Command{Use: "bar", Args: NoArgs, Run: emptyRun}
+	fooCmd := &Command{
+		Use:  "foo",
+		Args: ExactArgs(2),
+		Run:  func(_ *Command, args []string) { fooCmdArgs = args },
+	}
+	barCmd.AddCommand(fooCmd)
+	rootCmd.AddCommand(barCmd)
+
+	output, err := executeCommand(rootCmd, "bar", "foo", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	got := strings.Join(fooCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("fooCmdArgs expected: %v, got: %v", expected, got)
+	}
+}
+
+func TestFlagLong(t *testing.T) {
+	var cArgs []string
+	c := &Command{
+		Use:  "c",
+		Args: ArbitraryArgs,
+		Run:  func(_ *Command, args []string) { cArgs = args },
+	}
+
+	var intFlagValue int
+	var stringFlagValue string
+	c.Flags().IntVar(&intFlagValue, "intf", -1, "")
+	c.Flags().StringVar(&stringFlagValue, "sf", "", "")
+
+	output, err := executeCommand(c, "--intf=7", "--sf=abc", "one", "--", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", err)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if c.ArgsLenAtDash() != 1 {
+		t.Errorf("Expected ArgsLenAtDash: %v but got %v", 1, c.ArgsLenAtDash())
+	}
+	if intFlagValue != 7 {
+		t.Errorf("Expected intFlagValue: %v, got %v", 7, intFlagValue)
+	}
+	if stringFlagValue != "abc" {
+		t.Errorf("Expected stringFlagValue: %q, got %q", "abc", stringFlagValue)
+	}
+
+	got := strings.Join(cArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("Expected arguments: %q, got %q", expected, got)
+	}
+}
+
+func TestFlagShort(t *testing.T) {
+	var cArgs []string
+	c := &Command{
+		Use:  "c",
+		Args: ArbitraryArgs,
+		Run:  func(_ *Command, args []string) { cArgs = args },
+	}
+
+	var intFlagValue int
+	var stringFlagValue string
+	c.Flags().IntVarP(&intFlagValue, "intf", "i", -1, "")
+	c.Flags().StringVarP(&stringFlagValue, "sf", "s", "", "")
+
+	output, err := executeCommand(c, "-i", "7", "-sabc", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", err)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if intFlagValue != 7 {
+		t.Errorf("Expected flag value: %v, got %v", 7, intFlagValue)
+	}
+	if stringFlagValue != "abc" {
+		t.Errorf("Expected stringFlagValue: %q, got %q", "abc", stringFlagValue)
+	}
+
+	got := strings.Join(cArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("Expected arguments: %q, got %q", expected, got)
+	}
+}
+
+func TestChildFlag(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+
+	var intFlagValue int
+	childCmd.Flags().IntVarP(&intFlagValue, "intf", "i", -1, "")
+
+	output, err := executeCommand(rootCmd, "child", "-i7")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", err)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if intFlagValue != 7 {
+		t.Errorf("Expected flag value: %v, got %v", 7, intFlagValue)
+	}
+}
+
+func TestChildFlagWithParentLocalFlag(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+
+	var intFlagValue int
+	rootCmd.Flags().StringP("sf", "s", "", "")
+	childCmd.Flags().IntVarP(&intFlagValue, "intf", "i", -1, "")
+
+	_, err := executeCommand(rootCmd, "child", "-i7", "-sabc")
+	if err == nil {
+		t.Errorf("Invalid flag should generate error")
+	}
+
+	checkStringContains(t, err.Error(), "unknown shorthand")
+
+	if intFlagValue != 7 {
+		t.Errorf("Expected flag value: %v, got %v", 7, intFlagValue)
+	}
+}
+
+func TestFlagInvalidInput(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	rootCmd.Flags().IntP("intf", "i", -1, "")
+
+	_, err := executeCommand(rootCmd, "-iabc")
+	if err == nil {
+		t.Errorf("Invalid flag value should generate error")
+	}
+
+	checkStringContains(t, err.Error(), "invalid syntax")
+}
+
+func TestFlagBeforeCommand(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+
+	var flagValue int
+	childCmd.Flags().IntVarP(&flagValue, "intf", "i", -1, "")
+
+	// With short flag.
+	_, err := executeCommand(rootCmd, "-i7", "child")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if flagValue != 7 {
+		t.Errorf("Expected flag value: %v, got %v", 7, flagValue)
+	}
+
+	// With long flag.
+	_, err = executeCommand(rootCmd, "--intf=8", "child")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if flagValue != 8 {
+		t.Errorf("Expected flag value: %v, got %v", 9, flagValue)
 	}
 }
 
@@ -45,11 +468,11 @@ func TestStripFlags(t *testing.T) {
 			[]string{"foo", "bar"},
 		},
 		{
-			[]string{"foo", "--bar", "-b"},
+			[]string{"foo", "--str", "-s"},
 			[]string{"foo"},
 		},
 		{
-			[]string{"-b", "foo", "--bar", "bar"},
+			[]string{"-s", "foo", "--str", "bar"},
 			[]string{},
 		},
 		{
@@ -65,7 +488,7 @@ func TestStripFlags(t *testing.T) {
 			[]string{"echo"},
 		},
 		{
-			[]string{"-ib", "echo", "-bfoo", "baz"},
+			[]string{"-ib", "echo", "-sfoo", "baz"},
 			[]string{"echo", "baz"},
 		},
 		{
@@ -73,15 +496,15 @@ func TestStripFlags(t *testing.T) {
 			[]string{"bar", "blah"},
 		},
 		{
-			[]string{"--int=baz", "-bbar", "-i", "foo", "blah"},
+			[]string{"--int=baz", "-sbar", "-i", "foo", "blah"},
 			[]string{"blah"},
 		},
 		{
-			[]string{"--cat", "bar", "-i", "foo", "blah"},
+			[]string{"--bool", "bar", "-i", "foo", "blah"},
 			[]string{"bar", "blah"},
 		},
 		{
-			[]string{"-c", "bar", "-i", "foo", "blah"},
+			[]string{"-b", "bar", "-i", "foo", "blah"},
 			[]string{"bar", "blah"},
 		},
 		{
@@ -94,61 +517,757 @@ func TestStripFlags(t *testing.T) {
 		},
 	}
 
-	cmdPrint := &Command{
-		Use:   "print [string to print]",
-		Short: "Print anything to the screen",
-		Long:  `an utterly useless command for testing.`,
-		Run: func(cmd *Command, args []string) {
-			tp = args
-		},
-	}
-
-	var flagi int
-	var flagstr string
-	var flagbool bool
-	cmdPrint.PersistentFlags().BoolVarP(&flagbool, "persist", "p", false, "help for persistent one")
-	cmdPrint.Flags().IntVarP(&flagi, "int", "i", 345, "help message for flag int")
-	cmdPrint.Flags().StringVarP(&flagstr, "bar", "b", "bar", "help message for flag string")
-	cmdPrint.Flags().BoolVarP(&flagbool, "cat", "c", false, "help message for flag bool")
+	c := &Command{Use: "c", Run: emptyRun}
+	c.PersistentFlags().BoolP("persist", "p", false, "")
+	c.Flags().IntP("int", "i", -1, "")
+	c.Flags().StringP("str", "s", "", "")
+	c.Flags().BoolP("bool", "b", false, "")
 
-	for _, test := range tests {
-		output := stripFlags(test.input, cmdPrint)
-		if !reflect.DeepEqual(test.output, output) {
-			t.Errorf("expected: %v, got: %v", test.output, output)
+	for i, test := range tests {
+		got := stripFlags(test.input, c)
+		if !reflect.DeepEqual(test.output, got) {
+			t.Errorf("(%v) Expected: %v, got: %v", i, test.output, got)
 		}
 	}
 }
 
 func TestDisableFlagParsing(t *testing.T) {
-	targs := []string{}
-	cmdPrint := &Command{
+	var cArgs []string
+	c := &Command{
+		Use:                "c",
 		DisableFlagParsing: true,
-		Run: func(cmd *Command, args []string) {
-			targs = args
+		Run: func(_ *Command, args []string) {
+			cArgs = args
 		},
 	}
+
 	args := []string{"cmd", "-v", "-race", "-file", "foo.go"}
-	cmdPrint.SetArgs(args)
-	err := cmdPrint.Execute()
+	output, err := executeCommand(c, args...)
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if !reflect.DeepEqual(args, cArgs) {
+		t.Errorf("Expected: %v, got: %v", args, cArgs)
+	}
+}
+
+func TestPersistentFlagsOnSameCommand(t *testing.T) {
+	var rootCmdArgs []string
+	rootCmd := &Command{
+		Use:  "root",
+		Args: ArbitraryArgs,
+		Run:  func(_ *Command, args []string) { rootCmdArgs = args },
+	}
+
+	var flagValue int
+	rootCmd.PersistentFlags().IntVarP(&flagValue, "intf", "i", -1, "")
+
+	output, err := executeCommand(rootCmd, "-i7", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
 	if err != nil {
-		t.Error(err)
+		t.Errorf("Unexpected error: %v", err)
 	}
-	if !reflect.DeepEqual(args, targs) {
-		t.Errorf("expected: %v, got: %v", args, targs)
+
+	got := strings.Join(rootCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("rootCmdArgs expected: %q, got %q", expected, got)
+	}
+	if flagValue != 7 {
+		t.Errorf("flagValue expected: %v, got %v", 7, flagValue)
+	}
+}
+
+// TestEmptyInputs checks,
+// if flags correctly parsed with blank strings in args.
+func TestEmptyInputs(t *testing.T) {
+	c := &Command{Use: "c", Run: emptyRun}
+
+	var flagValue int
+	c.Flags().IntVarP(&flagValue, "intf", "i", -1, "")
+
+	output, err := executeCommand(c, "", "-i7", "")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if flagValue != 7 {
+		t.Errorf("flagValue expected: %v, got %v", 7, flagValue)
+	}
+}
+
+func TestOverwrittenFlag(t *testing.T) {
+	// TODO: This test fails, but should work.
+	t.Skip()
+
+	parent := &Command{Use: "parent", Run: emptyRun}
+	child := &Command{Use: "child", Run: emptyRun}
+
+	parent.PersistentFlags().Bool("boolf", false, "")
+	parent.PersistentFlags().Int("intf", -1, "")
+	child.Flags().String("strf", "", "")
+	child.Flags().Int("intf", -1, "")
+
+	parent.AddCommand(child)
+
+	childInherited := child.InheritedFlags()
+	childLocal := child.LocalFlags()
+
+	if childLocal.Lookup("strf") == nil {
+		t.Error(`LocalFlags expected to contain "strf", got "nil"`)
+	}
+	if childInherited.Lookup("boolf") == nil {
+		t.Error(`InheritedFlags expected to contain "boolf", got "nil"`)
+	}
+
+	if childInherited.Lookup("intf") != nil {
+		t.Errorf(`InheritedFlags should not contain overwritten flag "intf"`)
+	}
+	if childLocal.Lookup("intf") == nil {
+		t.Error(`LocalFlags expected to contain "intf", got "nil"`)
+	}
+}
+
+func TestPersistentFlagsOnChild(t *testing.T) {
+	var childCmdArgs []string
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{
+		Use:  "child",
+		Args: ArbitraryArgs,
+		Run:  func(_ *Command, args []string) { childCmdArgs = args },
+	}
+	rootCmd.AddCommand(childCmd)
+
+	var parentFlagValue int
+	var childFlagValue int
+	rootCmd.PersistentFlags().IntVarP(&parentFlagValue, "parentf", "p", -1, "")
+	childCmd.Flags().IntVarP(&childFlagValue, "childf", "c", -1, "")
+
+	output, err := executeCommand(rootCmd, "child", "-c7", "-p8", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	got := strings.Join(childCmdArgs, " ")
+	expected := "one two"
+	if got != expected {
+		t.Errorf("childCmdArgs expected: %q, got %q", expected, got)
+	}
+	if parentFlagValue != 8 {
+		t.Errorf("parentFlagValue expected: %v, got %v", 8, parentFlagValue)
+	}
+	if childFlagValue != 7 {
+		t.Errorf("childFlagValue expected: %v, got %v", 7, childFlagValue)
+	}
+}
+
+func TestRequiredFlags(t *testing.T) {
+	c := &Command{Use: "c", Run: emptyRun}
+	c.Flags().String("foo1", "", "")
+	c.MarkFlagRequired("foo1")
+	c.Flags().String("foo2", "", "")
+	c.MarkFlagRequired("foo2")
+	c.Flags().String("bar", "", "")
+
+	expected := fmt.Sprintf("Required flag(s) %q, %q have/has not been set", "foo1", "foo2")
+
+	_, err := executeCommand(c)
+	got := err.Error()
+
+	if got != expected {
+		t.Errorf("Expected error: %q, got: %q", expected, got)
+	}
+}
+
+func TestPersistentRequiredFlags(t *testing.T) {
+	parent := &Command{Use: "parent", Run: emptyRun}
+	parent.PersistentFlags().String("foo1", "", "")
+	parent.MarkPersistentFlagRequired("foo1")
+	parent.PersistentFlags().String("foo2", "", "")
+	parent.MarkPersistentFlagRequired("foo2")
+	parent.Flags().String("foo3", "", "")
+
+	child := &Command{Use: "child", Run: emptyRun}
+	child.Flags().String("bar1", "", "")
+	child.MarkFlagRequired("bar1")
+	child.Flags().String("bar2", "", "")
+	child.MarkFlagRequired("bar2")
+	child.Flags().String("bar3", "", "")
+
+	parent.AddCommand(child)
+
+	expected := fmt.Sprintf("Required flag(s) %q, %q, %q, %q have/has not been set", "bar1", "bar2", "foo1", "foo2")
+
+	_, err := executeCommand(parent, "child")
+	if err.Error() != expected {
+		t.Errorf("Expected %q, got %q", expected, err.Error())
 	}
 }
 
 func TestInitHelpFlagMergesFlags(t *testing.T) {
 	usage := "custom flag"
-	baseCmd := Command{Use: "testcmd"}
-	baseCmd.PersistentFlags().Bool("help", false, usage)
-	cmd := Command{Use: "do"}
-	baseCmd.AddCommand(&cmd)
+	rootCmd := &Command{Use: "root"}
+	rootCmd.PersistentFlags().Bool("help", false, "custom flag")
+	childCmd := &Command{Use: "child"}
+	rootCmd.AddCommand(childCmd)
+
+	childCmd.InitDefaultHelpFlag()
+	got := childCmd.Flags().Lookup("help").Usage
+	if got != usage {
+		t.Errorf("Expected the help flag from the root command with usage: %v\nGot the default with usage: %v", usage, got)
+	}
+}
+
+func TestHelpCommandExecuted(t *testing.T) {
+	rootCmd := &Command{Use: "root", Long: "Long description", Run: emptyRun}
+	rootCmd.AddCommand(&Command{Use: "child", Run: emptyRun})
+
+	output, err := executeCommand(rootCmd, "help")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, rootCmd.Long)
+}
 
-	cmd.InitDefaultHelpFlag()
-	actual := cmd.Flags().Lookup("help").Usage
-	if actual != usage {
-		t.Fatalf("Expected the help flag from the base command with usage '%s', but got the default with usage '%s'", usage, actual)
+func TestHelpCommandExecutedOnChild(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Long: "Long description", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+
+	output, err := executeCommand(rootCmd, "help", "child")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, childCmd.Long)
+}
+
+func TestSetHelpCommand(t *testing.T) {
+	c := &Command{Use: "c", Run: emptyRun}
+	c.AddCommand(&Command{Use: "empty", Run: emptyRun})
+
+	expected := "WORKS"
+	c.SetHelpCommand(&Command{
+		Use:   "help [command]",
+		Short: "Help about any command",
+		Long: `Help provides help for any command in the application.
+	Simply type ` + c.Name() + ` help [path to command] for full details.`,
+		Run: func(c *Command, _ []string) { c.Print(expected) },
+	})
+
+	got, err := executeCommand(c, "help")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if got != expected {
+		t.Errorf("Expected to contain %q, got %q", expected, got)
+	}
+}
+
+func TestHelpFlagExecuted(t *testing.T) {
+	rootCmd := &Command{Use: "root", Long: "Long description", Run: emptyRun}
+
+	output, err := executeCommand(rootCmd, "--help")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, rootCmd.Long)
+}
+
+func TestHelpFlagExecutedOnChild(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Long: "Long description", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+
+	output, err := executeCommand(rootCmd, "child", "--help")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, childCmd.Long)
+}
+
+// TestHelpFlagInHelp checks,
+// if '--help' flag is shown in help for child (executing `parent help child`),
+// that has no other flags.
+// Related to https://github.com/spf13/cobra/issues/302.
+func TestHelpFlagInHelp(t *testing.T) {
+	parentCmd := &Command{Use: "parent", Run: func(*Command, []string) {}}
+
+	childCmd := &Command{Use: "child", Run: func(*Command, []string) {}}
+	parentCmd.AddCommand(childCmd)
+
+	output, err := executeCommand(parentCmd, "help", "child")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, "[flags]")
+}
+
+func TestFlagsInUsage(t *testing.T) {
+	rootCmd := &Command{Use: "root", Args: NoArgs, Run: func(*Command, []string) {}}
+	output, err := executeCommand(rootCmd, "--help")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, "[flags]")
+}
+
+func TestHelpExecutedOnNonRunnableChild(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Long: "Long description"}
+	rootCmd.AddCommand(childCmd)
+
+	output, err := executeCommand(rootCmd, "child")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, childCmd.Long)
+}
+
+func TestUsageIsNotPrintedTwice(t *testing.T) {
+	var cmd = &Command{Use: "root"}
+	var sub = &Command{Use: "sub"}
+	cmd.AddCommand(sub)
+
+	output, _ := executeCommand(cmd, "")
+	if strings.Count(output, "Usage:") != 1 {
+		t.Error("Usage output is not printed exactly once")
+	}
+}
+
+func TestVisitParents(t *testing.T) {
+	c := &Command{Use: "app"}
+	sub := &Command{Use: "sub"}
+	dsub := &Command{Use: "dsub"}
+	sub.AddCommand(dsub)
+	c.AddCommand(sub)
+
+	total := 0
+	add := func(x *Command) {
+		total++
+	}
+	sub.VisitParents(add)
+	if total != 1 {
+		t.Errorf("Should have visited 1 parent but visited %d", total)
+	}
+
+	total = 0
+	dsub.VisitParents(add)
+	if total != 2 {
+		t.Errorf("Should have visited 2 parents but visited %d", total)
+	}
+
+	total = 0
+	c.VisitParents(add)
+	if total != 0 {
+		t.Errorf("Should have visited no parents but visited %d", total)
+	}
+}
+
+func TestSuggestions(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	timesCmd := &Command{
+		Use:        "times",
+		SuggestFor: []string{"counts"},
+		Run:        emptyRun,
+	}
+	rootCmd.AddCommand(timesCmd)
+
+	templateWithSuggestions := "Error: unknown command \"%s\" for \"root\"\n\nDid you mean this?\n\t%s\n\nRun 'root --help' for usage.\n"
+	templateWithoutSuggestions := "Error: unknown command \"%s\" for \"root\"\nRun 'root --help' for usage.\n"
+
+	tests := map[string]string{
+		"time":     "times",
+		"tiems":    "times",
+		"tims":     "times",
+		"timeS":    "times",
+		"rimes":    "times",
+		"ti":       "times",
+		"t":        "times",
+		"timely":   "times",
+		"ri":       "",
+		"timezone": "",
+		"foo":      "",
+		"counts":   "times",
+	}
+
+	for typo, suggestion := range tests {
+		for _, suggestionsDisabled := range []bool{true, false} {
+			rootCmd.DisableSuggestions = suggestionsDisabled
+
+			var expected string
+			output, _ := executeCommand(rootCmd, typo)
+
+			if suggestion == "" || suggestionsDisabled {
+				expected = fmt.Sprintf(templateWithoutSuggestions, typo)
+			} else {
+				expected = fmt.Sprintf(templateWithSuggestions, typo, suggestion)
+			}
+
+			if output != expected {
+				t.Errorf("Unexpected response.\nExpected:\n %q\nGot:\n %q\n", expected, output)
+			}
+		}
+	}
+}
+
+func TestRemoveCommand(t *testing.T) {
+	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+	rootCmd.RemoveCommand(childCmd)
+
+	_, err := executeCommand(rootCmd, "child")
+	if err == nil {
+		t.Error("Expected error on calling removed command. Got nil.")
+	}
+}
+
+func TestReplaceCommandWithRemove(t *testing.T) {
+	childUsed := 0
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	child1Cmd := &Command{
+		Use: "child",
+		Run: func(*Command, []string) { childUsed = 1 },
+	}
+	child2Cmd := &Command{
+		Use: "child",
+		Run: func(*Command, []string) { childUsed = 2 },
+	}
+	rootCmd.AddCommand(child1Cmd)
+	rootCmd.RemoveCommand(child1Cmd)
+	rootCmd.AddCommand(child2Cmd)
+
+	output, err := executeCommand(rootCmd, "child")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if childUsed == 1 {
+		t.Error("Removed command shouldn't be called")
+	}
+	if childUsed != 2 {
+		t.Error("Replacing command should have been called but didn't")
+	}
+}
+
+func TestDeprecatedCommand(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	deprecatedCmd := &Command{
+		Use:        "deprecated",
+		Deprecated: "This command is deprecated",
+		Run:        emptyRun,
+	}
+	rootCmd.AddCommand(deprecatedCmd)
+
+	output, err := executeCommand(rootCmd, "deprecated")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, output, deprecatedCmd.Deprecated)
+}
+
+func TestHooks(t *testing.T) {
+	var (
+		persPreArgs  string
+		preArgs      string
+		runArgs      string
+		postArgs     string
+		persPostArgs string
+	)
+
+	c := &Command{
+		Use: "c",
+		PersistentPreRun: func(_ *Command, args []string) {
+			persPreArgs = strings.Join(args, " ")
+		},
+		PreRun: func(_ *Command, args []string) {
+			preArgs = strings.Join(args, " ")
+		},
+		Run: func(_ *Command, args []string) {
+			runArgs = strings.Join(args, " ")
+		},
+		PostRun: func(_ *Command, args []string) {
+			postArgs = strings.Join(args, " ")
+		},
+		PersistentPostRun: func(_ *Command, args []string) {
+			persPostArgs = strings.Join(args, " ")
+		},
+	}
+
+	output, err := executeCommand(c, "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if persPreArgs != "one two" {
+		t.Errorf("Expected persPreArgs %q, got %q", "one two", persPreArgs)
+	}
+	if preArgs != "one two" {
+		t.Errorf("Expected preArgs %q, got %q", "one two", preArgs)
+	}
+	if runArgs != "one two" {
+		t.Errorf("Expected runArgs %q, got %q", "one two", runArgs)
+	}
+	if postArgs != "one two" {
+		t.Errorf("Expected postArgs %q, got %q", "one two", postArgs)
+	}
+	if persPostArgs != "one two" {
+		t.Errorf("Expected persPostArgs %q, got %q", "one two", persPostArgs)
+	}
+}
+
+func TestPersistentHooks(t *testing.T) {
+	var (
+		parentPersPreArgs  string
+		parentPreArgs      string
+		parentRunArgs      string
+		parentPostArgs     string
+		parentPersPostArgs string
+	)
+
+	var (
+		childPersPreArgs  string
+		childPreArgs      string
+		childRunArgs      string
+		childPostArgs     string
+		childPersPostArgs string
+	)
+
+	parentCmd := &Command{
+		Use: "parent",
+		PersistentPreRun: func(_ *Command, args []string) {
+			parentPersPreArgs = strings.Join(args, " ")
+		},
+		PreRun: func(_ *Command, args []string) {
+			parentPreArgs = strings.Join(args, " ")
+		},
+		Run: func(_ *Command, args []string) {
+			parentRunArgs = strings.Join(args, " ")
+		},
+		PostRun: func(_ *Command, args []string) {
+			parentPostArgs = strings.Join(args, " ")
+		},
+		PersistentPostRun: func(_ *Command, args []string) {
+			parentPersPostArgs = strings.Join(args, " ")
+		},
+	}
+
+	childCmd := &Command{
+		Use: "child",
+		PersistentPreRun: func(_ *Command, args []string) {
+			childPersPreArgs = strings.Join(args, " ")
+		},
+		PreRun: func(_ *Command, args []string) {
+			childPreArgs = strings.Join(args, " ")
+		},
+		Run: func(_ *Command, args []string) {
+			childRunArgs = strings.Join(args, " ")
+		},
+		PostRun: func(_ *Command, args []string) {
+			childPostArgs = strings.Join(args, " ")
+		},
+		PersistentPostRun: func(_ *Command, args []string) {
+			childPersPostArgs = strings.Join(args, " ")
+		},
+	}
+	parentCmd.AddCommand(childCmd)
+
+	output, err := executeCommand(parentCmd, "child", "one", "two")
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	// TODO: This test fails, but should not.
+	// Related to https://github.com/spf13/cobra/issues/252.
+	//
+	// if parentPersPreArgs != "one two" {
+	// 	t.Errorf("Expected parentPersPreArgs %q, got %q", "one two", parentPersPreArgs)
+	// }
+	if parentPreArgs != "" {
+		t.Errorf("Expected blank parentPreArgs, got %q", parentPreArgs)
+	}
+	if parentRunArgs != "" {
+		t.Errorf("Expected blank parentRunArgs, got %q", parentRunArgs)
+	}
+	if parentPostArgs != "" {
+		t.Errorf("Expected blank parentPostArgs, got %q", parentPostArgs)
+	}
+	// TODO: This test fails, but should not.
+	// Related to https://github.com/spf13/cobra/issues/252.
+	//
+	// if parentPersPostArgs != "one two" {
+	// 	t.Errorf("Expected parentPersPostArgs %q, got %q", "one two", parentPersPostArgs)
+	// }
+
+	if childPersPreArgs != "one two" {
+		t.Errorf("Expected childPersPreArgs %q, got %q", "one two", childPersPreArgs)
+	}
+	if childPreArgs != "one two" {
+		t.Errorf("Expected childPreArgs %q, got %q", "one two", childPreArgs)
+	}
+	if childRunArgs != "one two" {
+		t.Errorf("Expected childRunArgs %q, got %q", "one two", childRunArgs)
+	}
+	if childPostArgs != "one two" {
+		t.Errorf("Expected childPostArgs %q, got %q", "one two", childPostArgs)
+	}
+	if childPersPostArgs != "one two" {
+		t.Errorf("Expected childPersPostArgs %q, got %q", "one two", childPersPostArgs)
+	}
+}
+
+// Related to https://github.com/spf13/cobra/issues/521.
+func TestGlobalNormFuncPropagation(t *testing.T) {
+	normFunc := func(f *pflag.FlagSet, name string) pflag.NormalizedName {
+		return pflag.NormalizedName(name)
+	}
+
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun}
+	rootCmd.AddCommand(childCmd)
+
+	rootCmd.SetGlobalNormalizationFunc(normFunc)
+	if reflect.ValueOf(normFunc).Pointer() != reflect.ValueOf(rootCmd.GlobalNormalizationFunc()).Pointer() {
+		t.Error("rootCmd seems to have a wrong normalization function")
+	}
+
+	if reflect.ValueOf(normFunc).Pointer() != reflect.ValueOf(childCmd.GlobalNormalizationFunc()).Pointer() {
+		t.Error("childCmd should have had the normalization function of rootCmd")
+	}
+}
+
+// Related to https://github.com/spf13/cobra/issues/521.
+func TestNormPassedOnLocal(t *testing.T) {
+	toUpper := func(f *pflag.FlagSet, name string) pflag.NormalizedName {
+		return pflag.NormalizedName(strings.ToUpper(name))
+	}
+
+	c := &Command{}
+	c.Flags().Bool("flagname", true, "this is a dummy flag")
+	c.SetGlobalNormalizationFunc(toUpper)
+	if c.LocalFlags().Lookup("flagname") != c.LocalFlags().Lookup("FLAGNAME") {
+		t.Error("Normalization function should be passed on to Local flag set")
+	}
+}
+
+// Related to https://github.com/spf13/cobra/issues/521.
+func TestNormPassedOnInherited(t *testing.T) {
+	toUpper := func(f *pflag.FlagSet, name string) pflag.NormalizedName {
+		return pflag.NormalizedName(strings.ToUpper(name))
+	}
+
+	c := &Command{}
+	c.SetGlobalNormalizationFunc(toUpper)
+
+	child1 := &Command{}
+	c.AddCommand(child1)
+
+	c.PersistentFlags().Bool("flagname", true, "")
+
+	child2 := &Command{}
+	c.AddCommand(child2)
+
+	inherited := child1.InheritedFlags()
+	if inherited.Lookup("flagname") == nil || inherited.Lookup("flagname") != inherited.Lookup("FLAGNAME") {
+		t.Error("Normalization function should be passed on to inherited flag set in command added before flag")
+	}
+
+	inherited = child2.InheritedFlags()
+	if inherited.Lookup("flagname") == nil || inherited.Lookup("flagname") != inherited.Lookup("FLAGNAME") {
+		t.Error("Normalization function should be passed on to inherited flag set in command added after flag")
+	}
+}
+
+// Related to https://github.com/spf13/cobra/issues/521.
+func TestConsistentNormalizedName(t *testing.T) {
+	toUpper := func(f *pflag.FlagSet, name string) pflag.NormalizedName {
+		return pflag.NormalizedName(strings.ToUpper(name))
+	}
+	n := func(f *pflag.FlagSet, name string) pflag.NormalizedName {
+		return pflag.NormalizedName(name)
+	}
+
+	c := &Command{}
+	c.Flags().Bool("flagname", true, "")
+	c.SetGlobalNormalizationFunc(toUpper)
+	c.SetGlobalNormalizationFunc(n)
+
+	if c.LocalFlags().Lookup("flagname") == c.LocalFlags().Lookup("FLAGNAME") {
+		t.Error("Normalizing flag names should not result in duplicate flags")
+	}
+}
+
+func TestFlagOnPflagCommandLine(t *testing.T) {
+	flagName := "flagOnCommandLine"
+	pflag.String(flagName, "", "about my flag")
+
+	c := &Command{Use: "c", Run: emptyRun}
+	c.AddCommand(&Command{Use: "child", Run: emptyRun})
+
+	output, _ := executeCommand(c, "--help")
+	checkStringContains(t, output, flagName)
+
+	resetCommandLineFlagSet()
+}
+
+// TestHiddenCommandExecutes checks,
+// if hidden commands run as intended.
+func TestHiddenCommandExecutes(t *testing.T) {
+	executed := false
+	c := &Command{
+		Use:    "c",
+		Hidden: true,
+		Run:    func(*Command, []string) { executed = true },
+	}
+
+	output, err := executeCommand(c)
+	if output != "" {
+		t.Errorf("Unexpected output: %v", output)
+	}
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	if !executed {
+		t.Error("Hidden command should have been executed")
+	}
+}
+
+// test to ensure hidden commands do not show up in usage/help text
+func TestHiddenCommandIsHidden(t *testing.T) {
+	c := &Command{Use: "c", Hidden: true, Run: emptyRun}
+	if c.IsAvailableCommand() {
+		t.Errorf("Hidden command should be unavailable")
 	}
 }
 
@@ -158,15 +1277,16 @@ func TestCommandsAreSorted(t *testing.T) {
 	originalNames := []string{"middle", "zlast", "afirst"}
 	expectedNames := []string{"afirst", "middle", "zlast"}
 
-	var tmpCommand = &Command{Use: "tmp"}
+	var rootCmd = &Command{Use: "root"}
 
 	for _, name := range originalNames {
-		tmpCommand.AddCommand(&Command{Use: name})
+		rootCmd.AddCommand(&Command{Use: name})
 	}
 
-	for i, c := range tmpCommand.Commands() {
-		if expectedNames[i] != c.Name() {
-			t.Errorf("expected: %s, got: %s", expectedNames[i], c.Name())
+	for i, c := range rootCmd.Commands() {
+		got := c.Name()
+		if expectedNames[i] != got {
+			t.Errorf("Expected: %s, got: %s", expectedNames[i], got)
 		}
 	}
 
@@ -178,15 +1298,16 @@ func TestEnableCommandSortingIsDisabled(t *testing.T) {
 
 	originalNames := []string{"middle", "zlast", "afirst"}
 
-	var tmpCommand = &Command{Use: "tmp"}
+	var rootCmd = &Command{Use: "root"}
 
 	for _, name := range originalNames {
-		tmpCommand.AddCommand(&Command{Use: name})
+		rootCmd.AddCommand(&Command{Use: name})
 	}
 
-	for i, c := range tmpCommand.Commands() {
-		if originalNames[i] != c.Name() {
-			t.Errorf("expected: %s, got: %s", originalNames[i], c.Name())
+	for i, c := range rootCmd.Commands() {
+		got := c.Name()
+		if originalNames[i] != got {
+			t.Errorf("expected: %s, got: %s", originalNames[i], got)
 		}
 	}
 
@@ -194,33 +1315,27 @@ func TestEnableCommandSortingIsDisabled(t *testing.T) {
 }
 
 func TestSetOutput(t *testing.T) {
-	cmd := &Command{}
-	cmd.SetOutput(nil)
-	if out := cmd.OutOrStdout(); out != os.Stdout {
-		t.Fatalf("expected setting output to nil to revert back to stdout, got %v", out)
+	c := &Command{}
+	c.SetOutput(nil)
+	if out := c.OutOrStdout(); out != os.Stdout {
+		t.Errorf("Expected setting output to nil to revert back to stdout")
 	}
 }
 
 func TestFlagErrorFunc(t *testing.T) {
-	cmd := &Command{
-		Use: "print",
-		RunE: func(cmd *Command, args []string) error {
-			return nil
-		},
-	}
-	expectedFmt := "This is expected: %s"
+	c := &Command{Use: "c", Run: emptyRun}
 
-	cmd.SetFlagErrorFunc(func(c *Command, err error) error {
+	expectedFmt := "This is expected: %v"
+	c.SetFlagErrorFunc(func(_ *Command, err error) error {
 		return fmt.Errorf(expectedFmt, err)
 	})
-	cmd.SetArgs([]string{"--bogus-flag"})
-	cmd.SetOutput(new(bytes.Buffer))
 
-	err := cmd.Execute()
+	_, err := executeCommand(c, "--unknown-flag")
 
-	expected := fmt.Sprintf(expectedFmt, "unknown flag: --bogus-flag")
-	if err.Error() != expected {
-		t.Errorf("expected %v, got %v", expected, err.Error())
+	got := err.Error()
+	expected := fmt.Sprintf(expectedFmt, "unknown flag: --unknown-flag")
+	if got != expected {
+		t.Errorf("Expected %v, got %v", expected, got)
 	}
 }
 
@@ -228,19 +1343,19 @@ func TestFlagErrorFunc(t *testing.T) {
 // if cmd.LocalFlags() is unsorted when cmd.Flags().SortFlags set to false.
 // Related to https://github.com/spf13/cobra/issues/404.
 func TestSortedFlags(t *testing.T) {
-	cmd := &Command{}
-	cmd.Flags().SortFlags = false
+	c := &Command{}
+	c.Flags().SortFlags = false
 	names := []string{"C", "B", "A", "D"}
 	for _, name := range names {
-		cmd.Flags().Bool(name, false, "")
+		c.Flags().Bool(name, false, "")
 	}
 
 	i := 0
-	cmd.LocalFlags().VisitAll(func(f *pflag.Flag) {
+	c.LocalFlags().VisitAll(func(f *pflag.Flag) {
 		if i == len(names) {
 			return
 		}
-		if isStringInStringSlice(f.Name, names) {
+		if stringInSlice(f.Name, names) {
 			if names[i] != f.Name {
 				t.Errorf("Incorrect order. Expected %v, got %v", names[i], f.Name)
 			}
@@ -249,101 +1364,145 @@ func TestSortedFlags(t *testing.T) {
 	})
 }
 
-// contains checks, if s is in ss.
-func isStringInStringSlice(s string, ss []string) bool {
-	for _, v := range ss {
-		if v == s {
-			return true
-		}
-	}
-	return false
-}
-
-// TestHelpFlagInHelp checks,
-// if '--help' flag is shown in help for child (executing `parent help child`),
-// that has no other flags.
-// Related to https://github.com/spf13/cobra/issues/302.
-func TestHelpFlagInHelp(t *testing.T) {
-	output := new(bytes.Buffer)
-	parent := &Command{Use: "parent", Run: func(*Command, []string) {}}
-	parent.SetOutput(output)
-
-	child := &Command{Use: "child", Run: func(*Command, []string) {}}
-	parent.AddCommand(child)
-
-	parent.SetArgs([]string{"help", "child"})
-	err := parent.Execute()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if !strings.Contains(output.String(), "[flags]") {
-		t.Errorf("\nExpecting to contain: %v\nGot: %v", "[flags]", output.String())
-	}
-}
-
 // TestMergeCommandLineToFlags checks,
 // if pflag.CommandLine is correctly merged to c.Flags() after first call
 // of c.mergePersistentFlags.
 // Related to https://github.com/spf13/cobra/issues/443.
 func TestMergeCommandLineToFlags(t *testing.T) {
 	pflag.Bool("boolflag", false, "")
-	c := &Command{Use: "c", Run: func(*Command, []string) {}}
+	c := &Command{Use: "c", Run: emptyRun}
 	c.mergePersistentFlags()
 	if c.Flags().Lookup("boolflag") == nil {
 		t.Fatal("Expecting to have flag from CommandLine in c.Flags()")
 	}
 
-	// Reset pflag.CommandLine flagset.
-	pflag.CommandLine = pflag.NewFlagSet(os.Args[0], pflag.ExitOnError)
+	resetCommandLineFlagSet()
 }
 
 // TestUseDeprecatedFlags checks,
 // if cobra.Execute() prints a message, if a deprecated flag is used.
 // Related to https://github.com/spf13/cobra/issues/463.
 func TestUseDeprecatedFlags(t *testing.T) {
-	c := &Command{Use: "c", Run: func(*Command, []string) {}}
-	output := new(bytes.Buffer)
-	c.SetOutput(output)
+	c := &Command{Use: "c", Run: emptyRun}
 	c.Flags().BoolP("deprecated", "d", false, "deprecated flag")
 	c.Flags().MarkDeprecated("deprecated", "This flag is deprecated")
 
-	c.SetArgs([]string{"c", "-d"})
-	if err := c.Execute(); err != nil {
+	output, err := executeCommand(c, "c", "-d")
+	if err != nil {
 		t.Error("Unexpected error:", err)
 	}
-	if !strings.Contains(output.String(), "This flag is deprecated") {
-		t.Errorf("Expected to contain deprecated message, but got %q", output.String())
+	checkStringContains(t, output, "This flag is deprecated")
+}
+
+func TestTraverseWithParentFlags(t *testing.T) {
+	rootCmd := &Command{Use: "root", TraverseChildren: true}
+	rootCmd.Flags().String("str", "", "")
+	rootCmd.Flags().BoolP("bool", "b", false, "")
+
+	childCmd := &Command{Use: "child"}
+	childCmd.Flags().Int("int", -1, "")
+
+	rootCmd.AddCommand(childCmd)
+
+	c, args, err := rootCmd.Traverse([]string{"-b", "--str", "ok", "child", "--int"})
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if len(args) != 1 && args[0] != "--add" {
+		t.Errorf("Wrong args: %v", args)
+	}
+	if c.Name() != childCmd.Name() {
+		t.Errorf("Expected command: %q, got: %q", childCmd.Name(), c.Name())
 	}
 }
 
-// TestSetHelpCommand checks, if SetHelpCommand works correctly.
-func TestSetHelpCommand(t *testing.T) {
-	c := &Command{Use: "c", Run: func(*Command, []string) {}}
-	output := new(bytes.Buffer)
-	c.SetOutput(output)
-	c.SetArgs([]string{"help"})
-
-	// Help will not be shown, if c has no subcommands.
-	c.AddCommand(&Command{
-		Use: "empty",
-		Run: func(cmd *Command, args []string) {},
-	})
+func TestTraverseNoParentFlags(t *testing.T) {
+	rootCmd := &Command{Use: "root", TraverseChildren: true}
+	rootCmd.Flags().String("foo", "", "foo things")
 
-	correctMessage := "WORKS"
-	c.SetHelpCommand(&Command{
-		Use:   "help [command]",
-		Short: "Help about any command",
-		Long: `Help provides help for any command in the application.
-	Simply type ` + c.Name() + ` help [path to command] for full details.`,
-		Run: func(c *Command, args []string) { c.Print(correctMessage) },
-	})
+	childCmd := &Command{Use: "child"}
+	childCmd.Flags().String("str", "", "")
+	rootCmd.AddCommand(childCmd)
 
-	if err := c.Execute(); err != nil {
-		t.Error("Unexpected error:", err)
+	c, args, err := rootCmd.Traverse([]string{"child"})
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if len(args) != 0 {
+		t.Errorf("Wrong args %v", args)
+	}
+	if c.Name() != childCmd.Name() {
+		t.Errorf("Expected command: %q, got: %q", childCmd.Name(), c.Name())
+	}
+}
+
+func TestTraverseWithBadParentFlags(t *testing.T) {
+	rootCmd := &Command{Use: "root", TraverseChildren: true}
+
+	childCmd := &Command{Use: "child"}
+	childCmd.Flags().String("str", "", "")
+	rootCmd.AddCommand(childCmd)
+
+	expected := "unknown flag: --str"
+
+	c, _, err := rootCmd.Traverse([]string{"--str", "ok", "child"})
+	if err == nil || !strings.Contains(err.Error(), expected) {
+		t.Errorf("Expected error, %q, got %q", expected, err)
+	}
+	if c != nil {
+		t.Errorf("Expected nil command")
 	}
+}
+
+func TestTraverseWithBadChildFlag(t *testing.T) {
+	rootCmd := &Command{Use: "root", TraverseChildren: true}
+	rootCmd.Flags().String("str", "", "")
+
+	childCmd := &Command{Use: "child"}
+	rootCmd.AddCommand(childCmd)
+
+	// Expect no error because the last commands args shouldn't be parsed in
+	// Traverse.
+	c, args, err := rootCmd.Traverse([]string{"child", "--str"})
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if len(args) != 1 && args[0] != "--str" {
+		t.Errorf("Wrong args: %v", args)
+	}
+	if c.Name() != childCmd.Name() {
+		t.Errorf("Expected command %q, got: %q", childCmd.Name(), c.Name())
+	}
+}
+
+func TestTraverseWithTwoSubcommands(t *testing.T) {
+	rootCmd := &Command{Use: "root", TraverseChildren: true}
+
+	subCmd := &Command{Use: "sub", TraverseChildren: true}
+	rootCmd.AddCommand(subCmd)
+
+	subsubCmd := &Command{
+		Use: "subsub",
+	}
+	subCmd.AddCommand(subsubCmd)
+
+	c, _, err := rootCmd.Traverse([]string{"sub", "subsub"})
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	if c.Name() != subsubCmd.Name() {
+		t.Fatalf("Expected command: %q, got %q", subsubCmd.Name(), c.Name())
+	}
+}
+
+// TestUpdateName checks if c.Name() updates on changed c.Use.
+// Related to https://github.com/spf13/cobra/pull/422#discussion_r143918343.
+func TestUpdateName(t *testing.T) {
+	c := &Command{Use: "name xyz"}
+	originalName := c.Name()
 
-	if output.String() != correctMessage {
-		t.Errorf("Expected to contain %q message, but got %q", correctMessage, output.String())
+	c.Use = "changedName abc"
+	if originalName == c.Name() || c.Name() != "changedName" {
+		t.Error("c.Name() should be updated on changed c.Use")
 	}
 }