func (s *Scanner) advance(n int) bool {
	if n < 0 {
		s.setErr(ErrNegativeAdvance)
		return false
	}
	if n > s.end-s.start {
		s.setErr(ErrAdvanceTooFar)
		return false
	}
	s.start += n
	return true
}

// setErr records the first error encountered.
func (s *Scanner) setErr(err error) {
	if s.err == nil || s.err == io.EOF {
		s.err = err
	}
}

    originalSystemErr = System.err

    System.setOut(object : PrintStream(OutputStream.nullOutputStream()) {})
    System.setErr(object : PrintStream(OutputStream.nullOutputStream()) {})
  }

  fun uninstall() {
    originalSystemOut.let {
      System.setOut(it)
    }
    originalSystemErr.let {
      System.setErr(it)
    }
  }

	_ = parent.PersistentFlags().String(parentFlag1, "", parentFlag1)
	_ = parent.PersistentFlags().String(parentFlag2, "", parentFlag2)
	var out bytes.Buffer
	parent.SetOut(&out)
	parent.SetErr(&out)

	child := &cobra.Command{
		Use: "child",
		Run: func(c *cobra.Command, args []string) {},
	}
	_ = parent.PersistentFlags().String(childFlag2, "", childFlag2)
	parent.AddCommand(child)

	WantException bool
}

func VerifyOutput(t *testing.T, cmd *cobra.Command, c TestCase) {
	t.Helper()

	cmd.SetArgs(c.Args)

	var out bytes.Buffer
	cmd.SetOut(&out)
	cmd.SetErr(&out)
	cmd.SilenceUsage = true

	fErr := cmd.Execute()
	output := out.String()

	if c.ExpectedOutput != "" && c.ExpectedOutput != output {
		t.Fatalf("Unexpected output for '%s %s'\n got: %q\nwant: %q", cmd.Name(),

	// Save listing...
	go func() {
		if err := saver.saveMetaCacheStream(listCtx, &meta, saveCh); err != nil {
			meta.setErr(err.Error())
		}
		cancel()
	}()

	// Do listing...
	go func(o listPathOptions) {
		err := z.listMerged(listCtx, o, inCh)
		if err != nil {
			meta.setErr(err.Error())
		}
		o.debugln("listAndSave: listing", o.ID, "finished with ", err)
	}(*o)

		return nil, nil
	}
	rootCmd := GetRootCmd(cli.NewFakeContext(&cli.NewFakeContextOption{
		Version: "25",
	}), args)
	var out bytes.Buffer
	rootCmd.SetOut(&out)
	rootCmd.SetErr(&out)

	err := rootCmd.Execute()
	if err != nil {
		t.Fatalf("failed to execute istioctl profile command: %v", err)
	}
	output := out.String()

//msgp:ignore metaCacheRPC
type metaCacheRPC struct {
	o      listPathOptions
	mu     sync.Mutex
	meta   *metacache
	rpc    *peerRESTClient
	cancel context.CancelFunc
}

func (m *metaCacheRPC) setErr(err string) {
	m.mu.Lock()
	defer m.mu.Unlock()
	meta := *m.meta
	if meta.status != scanStateError {
		meta.error = err
		meta.status = scanStateError
	} else {
		// An error is already set.
		return

`

func TestLogHelp(t *testing.T) {
	var out bytes.Buffer
	rootCmd := GetRootCmd([]string{"options"})
	rootCmd.SetOut(&out)
	rootCmd.SetErr(&out)

	fErr := rootCmd.Execute()
	if fErr != nil {
		t.Fatalf("options failed with %v and %q\n", fErr, out.String())
	}
	if !regexp.MustCompile(expectedOutput).Match(out.Bytes()) {

			if len(expectedOut) == 0 {
				t.Fatal("expected output is empty")
			}

			var out bytes.Buffer
			rootCmd := Cmd(ctx)
			rootCmd.SetArgs(tt.args)
			rootCmd.SetOut(&out)
			rootCmd.SetErr(&out)

			fErr := rootCmd.Execute()
			if fErr != nil {
				t.Fatal(fErr)
			}
			output := out.String()
			if output != expectedOut {
				t.Fatalf("expected %s, got %s", expectedOut, output)
			}

		})
	}
}

func verifyTestcaseOutput(t *testing.T, cmd *cobra.Command, c testcase) {
	t.Helper()

	var out bytes.Buffer
	cmd.SetArgs(c.args)
	cmd.SetOut(&out)
	cmd.SetErr(&out)
	cmd.SilenceUsage = true
	if c.namespace != "" {
		namespace = c.namespace
	}

	fErr := cmd.Execute()
	output := out.String()

	if c.expectedException {
		if fErr == nil {