type args struct {
		s string
	}
	tests := []struct {
		name string
		args args
		want bool
	}{
		// TODO: Add test cases.
		{
			"test1",
			args{
				"kafka",
			},
			true,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := IsPalindrome(tt.args.s); got != tt.want {
				t.Errorf("IsPalindrome() = %v, want %v", got, tt.want)
			}
		})
	}

import (
    "flag"
    "fmt"
    "io"
    "os"
    "strings"
)
var (
    n = flag.Bool("n", false, "omit trailing newline")
    s = flag.String("s", " ", "separator")
)
var out io.Writer = os.Stdout // modified during testing
func main() {
    flag.Parse()
    if err := echo(!*n, *s, flag.Args()); err != nil {
        fmt.Fprintf(os.Stderr, "echo: %v\n", err)
        os.Exit(1)
    }
}
func echo(newline bool, sep string, args []string) error {
    fmt.Fprint(out, strings.Join(args, sep))
    if newline {
        fmt.Fprintln(out)
    }
    return nil
}

import (
    "bytes"
    "fmt"
    "testing"
)
func TestEcho(t *testing.T) {
    var tests = []struct {
        newline bool
        sep     string
        args    []string
        want    string
    }{
        {true, "", []string{}, "\n"},
        {false, "", []string{}, ""},
        {true, "\t", []string{"one", "two", "three"}, "one\ttwo\tthree\n"},
        {true, ",", []string{"a", "b", "c"}, "a,b,c\n"},
        {false, ":", []string{"1", "2", "3"}, "1:2:3"},
    }
    for _, test := range tests {
        descr := fmt.Sprintf("echo(%v, %q, %q)",
            test.newline, test.sep, test.args)
        out = new(bytes.Buffer) // captured output
        if err := echo(test.newline, test.sep, test.args); err != nil {
            t.Errorf("%s failed: %v", descr, err)
            continue
        }
        got := out.(*bytes.Buffer).String()
        if got != test.want {
            t.Errorf("%s = %q, want %q", descr, got, test.want)
        }
    }
}

func BenchmarkIsPalindrome(b *testing.B) {
	for i := 0; i < b.N; i++ {
		IsPalindrome("A man, a plan, a canal: Panama")
	}
}
goos: windows
goarch: amd64
pkg: goprograme/src
cpu: Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz
BenchmarkIsPalindrome
BenchmarkIsPalindrome-4          2308773               502.9 ns/op

func IsPalindrome(s string) bool {
    letters := make([]rune, 0, len(s))
    for _, r := range s {
        if unicode.IsLetter(r) {
            letters = append(letters, unicode.ToLower(r))
        }
    }
    n := len(letters) / 2
    for i := 0; i < n; i++ {
        if letters[i] != letters[len(letters)-1-i] {
            return false
        }
    }
    return true
}