expectRuntimeCost  uint64
	}{
		{
			name:               "lowerAscii",
			expr:               "'ABCDEFGHIJ abcdefghij'.lowerAscii()",
			expectEsimatedCost: checker.CostEstimate{Min: 3, Max: 3},
			expectRuntimeCost:  3,
		},
		{
			name:               "lowerAsciiEquals",
			expr:               "'ABCDEFGHIJ abcdefghij'.lowerAscii() == 'abcdefghij ABCDEFGHIJ'.lowerAscii()",
			expectEsimatedCost: checker.CostEstimate{Min: 7, Max: 9},

		var cost uint64
		if len(args) > 0 {
			cost += traversalCost(args[0]) // these O(n) operations all cost roughly the cost of a single traversal
		}
		return &cost
	case "url", "lowerAscii", "upperAscii", "substring", "trim":
		if len(args) >= 1 {
			cost := uint64(math.Ceil(float64(actualSize(args[0])) * common.StringTraversalCostFactor))
			return &cost
		}
	case "replace", "split":

	if err != nil {
		return 0, &DNSError{Err: err.Error(), Name: network + "/" + service}
	}
	// Lowercase the C service name.
	for i, b := range cservice[:len(service)] {
		cservice[i] = lowerASCII(b)
	}
	var res *_C_struct_addrinfo
	gerrno, err := _C_getaddrinfo(nil, (*_C_char)(unsafe.Pointer(&cservice[0])), hints, &res)
	if gerrno != 0 {
		switch gerrno {
		case _C_EAI_SYSTEM: