Full, working code for "Writing a Simple Fuzzer in Python" at https://jmcph4.github.com/2018/01/19/writing-a-simple-fuzzer-in-python

fuzztut.py

import sys
from mph.program import Program
from fuzzbang.alphanumericfuzzer import AlphaNumericFuzzer

PATH_TO_NAME = "" # fill this in yourself

def run(string):
	"""
	Sends the provided string to the `name` program and runs it with that
	input. Returns the return value `name` gives us
	"""
	prog = Program(PATH_TO_NAME, [])
	prog.append_string_stdin(string)
	prog.exec()
	
	return prog.retval

def generate_input(n):
	"""
	Returns an alphanumeric string with a length no greater than n.
	"""
	fuzzer = AlphaNumericFuzzer(0, n)
	
	return f.generate()

if _name__ == "__main__":
	# usage
	if len(sys.argv) != 3:
		print("usage: python3 fuzztut.py num_cases max_length")
		exit(1)
		
	# command-line arguments	
	num_cases = int(sys.argv[1]) # number of test cases to run
	max_length = int(sys.argv[2]) # maximum length of each string
	   
	results = [] # list for storing the result of each test
	
	# main loop
	for i in range(num_cases):
		input = generate_input() # generate input string
		return_value = run(input) # run name with our input
		
		# save test results to our global results list
		test_result = {}
		test_result["num"] = i
		test_result["input"] = input
		test_result["output"] = return_value
		results.append(test_result)

	# print summary
	for test in results:
		print("Case #{:d}:".format(test["num"]))
		print("	IN: " + test["input"])
		print("	OUT: {:4d}".format(test["output"]))
		print("\n")