for _, tc := range trimFuncTests {
		trimmers := []struct {
			name string
			trim func(s []byte, f func(r rune) bool) []byte
			out  []byte
		}{
			{"TrimFunc", TrimFunc, tc.trimOut},
			{"TrimLeftFunc", TrimLeftFunc, tc.leftOut},
			{"TrimRightFunc", TrimRightFunc, tc.rightOut},
		}
		for _, trimmer := range trimmers {
			actual := trimmer.trim([]byte(tc.in), tc.f.f)
			if actual == nil && trimmer.out != nil {

	// Output:
	// gopher8257
}

func ExampleTrimLeftFunc() {
	fmt.Println(string(bytes.TrimLeftFunc([]byte("go-gopher"), unicode.IsLetter)))
	fmt.Println(string(bytes.TrimLeftFunc([]byte("go-gopher!"), unicode.IsPunct)))
	fmt.Println(string(bytes.TrimLeftFunc([]byte("1234go-gopher!567"), unicode.IsNumber)))
	// Output:
	// -gopher
	// go-gopher!
	// go-gopher!567
}