}
	}
	return true
}

func sliceOfString(s [][]byte) []string {
	result := make([]string, len(s))
	for i, v := range s {
		result[i] = string(v)
	}
	return result
}

// For ease of reading, the test cases use strings that are converted to byte
// slices before invoking the functions.

var abcd = "abcd"
var faces = "☺☻☹"
var commas = "1,2,3,4"
var dots = "1....2....3....4"

type BinOpTest struct {