creating a fuzzing example using a calculator.

examples/fuzzing/calculator_fuzz.go

@@ -0,0 +1,79 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"math/rand"
+	"strconv"
+	"strings"
+)
+
+func Calculator(num1, num2 float64, operator string) (float64, error) {
+	var result float64
+
+	switch operator {
+	case "-":
+		result = num1 - num2
+
+	case "+":
+		result = num1 + num2
+
+	case "/":
+		if num2 == 0 || num1 == 0 {
+			return 0, errors.New("Division by 0")
+		}
+	case "*":
+		result = num1 * num2
+	}
+
+	return result, nil
+}
+
+/*
+The go-fuzz testing tools operates on raw binary data
+Every input are in []bytes which are coverted to strings and
+The string is then split into three parts (two numbers and an operator) using strings.
+Split, and the numbers are parsed using strconv.ParseFloat. Finally,
+the Calculator function is called with the parsed numbers and operator.
+*/
+func Fuzz(data []byte) float64 {
+	//converts input data into string
+	inputs := strings.Split(string(data), ",")
+	//parse input numbers and operators
+	num1, err := strconv.ParseFloat(inputs[0], 64)
+	if err != nil {
+		return 0
+
+	}
+	num2, err := strconv.ParseFloat(inputs[1], 64)
+	if err != nil {
+		return 0
+	}
+	operators := inputs[2]
+	_, err = Calculator(num1, num2, operators)
+	if err != nil {
+		if err.Error() != "Division by 0" {
+			return 0
+		}
+	}
+	//returns a success
+	return 1
+}
+
+func main() {
+	// Seed the random number generator
+	rand.Seed(1234)
+
+	// Generate random input data
+	data := make([]byte, 64)
+	rand.Read(data)
+
+	result, err := Calculator(16, 18, "*")
+	if err != nil {
+		fmt.Println(err)
+	}
+	fmt.Println(result)
+
+	// Fuzz the Calculator function with the generated input data
+	Fuzz(data)
+}