mayhemmonkey 2025.2.20.post6

A tool for testing what happens if base functions of python except

MayhemMonkey

MayhemMonkey is a testing tool designed to simulate how your program might react to unexpected errors that can occur when executing basic built-in functions in Python. It helps ensure that your code is robust enough to handle a variety of errors gracefully.

Goal

The main goal of MayhemMonkey is to simulate errors in basic built-in functions to test how your program responds to unexpected failures. With mayhemmonkey, you can introduce different types of errors in critical Python functions like open, print, eval, etc., and ensure your application remains stable under these conditions.

Installation

Install MayhemMonkey easily using pip:

pip3 install mayhemmonkey

Usage

Here is a simple example of how to use MayhemMonkey in a Python project:

from mayhemmonkey import MayhemMonkey

mayhemmonkey = MayhemMonkey()

mayhemmonkey.set_function_error_rate("open", 0.5)
mayhemmonkey.set_function_group_error_rate("io", 0.3)

mayhemmonkey.install_faulty()

with open("test.txt", "w") as f:  # 50% Chance that it'll fail
    f.write("Hello world!")

print("This should be printed.")  # 30% it'll fail because it's in the group "io"

You can also set specific functions to fail after a certain amount of calls:

from mayhemmonkey import MayhemMonkey

mayhemmonkey = MayhemMonkey()

mayhemmonkey.set_function_fail_after_count("print", 3)

mayhemmonkey.install_faulty()

print("This should be printed.")
print("This should be printed.")
try:
    print("This shouldn't be printed.")
except Exception as e:
    print(f"Error: {e}")

print("This should be printed.")

Here, the 3rd print fails with some random error that print can give in real life.

Error Configuration

MayhemMonkey allows you to configure the error probability for various functions, function groups, or globally. The error probability is given as a decimal number between 0 and 1, where 0 means no errors and 1 guarantees an error.

Methods of the MayhemMonkey-object

Function	Description	Parameters
get_function_categories	Returns a dictionary of all function categories and their respective functions.	No parameters.
get_function_categories_as_list	Returns a list of tuples where each tuple contains the category name and its associated functions.	No parameters.
install_faulty	Patches built-in functions to introduce errors. Can only be called once.	No parameters.
set_function_error_rate	Sets the error probability for an individual function.	name (str or list): The function name, or a list of function names. rate (float): The error rate between 0 and 1.
set_function_group_error_rate	Sets the error probability for a group of functions.	group (str or list): The function group, or a list of group names. rate (float): The error rate between 0 and 1.
is_valid_exception_tuple_list	Checks if the provided object is a valid list of tuples with exception types and messages.	obj (list): A list of tuples of the form (ExceptionType, String).
add_exception_to_function	Adds a list of exceptions (tuples) to a function to simulate specific errors.	name (str): The function name. list_of_tuples_of_exceptions (list): List of tuples (ExceptionType, String).
set_function_fail_after_count	Sets the count after which a function will start failing with errors.	name (str): The function name. cnt (int): The count after which it will fail.
generate_function_categories_markdown_table	Generates a markdown table for function categories and their functions.	No parameters.
generate_function_errors_markdown_table	Generates a markdown table for functions and their associated errors.	No parameters.

Function Groups and Their Functions

Category	Functions
attributes	delattr, getattr, hasattr, property, setattr
collections	dict, frozenset, list, set, tuple
conversion	ascii, bin, bool, bytearray, bytes, chr, complex, float, format, hex, int, oct, ord, repr, str
evaluation	compile, eval, exec
exceptions	compile, eval, exec
functional	breakpoint, classmethod, staticmethod, super
hashing	hash
io	input, open, print
iteration	all, any, enumerate, filter, iter, len, map, next, range, reversed, sorted, zip
math	abs, divmod, max, min, pow, round, sum
reflection	__import__, callable, globals, id, isinstance, issubclass, locals, type, vars
slicing	slice

Error Types for Functions

MayhemMonkey can generate specific types of errors for each function. Here’s a list of the possible errors and their meanings:

Function	Errors
__import__	ImportError: Module not found TypeError: Invalid module name
abs	TypeError: Bad operand type for abs()
all	TypeError: Argument must be iterable
any	TypeError: Argument must be iterable
ascii	None
bin	TypeError: Object cannot be interpreted as an integer
bool	None
breakpoint	RuntimeError: Cannot start debugger
bytearray	TypeError: Invalid argument type ValueError: Negative size not allowed
bytes	TypeError: Invalid argument type ValueError: Negative size not allowed
callable	None
chr	ValueError: Argument out of range TypeError: Integer argument required
classmethod	TypeError: Invalid method reference
compile	SyntaxError: Compilation error TypeError: Invalid code object
complex	ValueError: Could not convert string to complex TypeError: Invalid type for complex()
delattr	AttributeError: Object has no such attribute TypeError: Invalid attribute name
dict	TypeError: Invalid dictionary construction
dir	TypeError: Invalid argument type
divmod	ZeroDivisionError: division by zero TypeError: Unsupported operand type
enumerate	TypeError: Object is not iterable
eval	SyntaxError: Invalid syntax TypeError: Expression not allowed RuntimeError: Unexpected runtime error
exec	SyntaxError: Invalid syntax RuntimeError: Unexpected runtime error
filter	TypeError: Function must be callable
float	ValueError: Could not convert string to float TypeError: Invalid type for float()
format	ValueError: Invalid format string
frozenset	TypeError: Invalid argument type
getattr	AttributeError: Object has no such attribute TypeError: Invalid attribute name
globals	None
hasattr	None
hash	TypeError: Unhashable type
hex	TypeError: Object cannot be interpreted as an integer
id	None
input	EOFError: End of file reached KeyboardInterrupt: Input interrupted
int	ValueError: Invalid literal for int() TypeError: Invalid type for int()
isinstance	TypeError: Second argument must be a type or tuple of types
issubclass	TypeError: Second argument must be a type or tuple of types
iter	TypeError: Object is not iterable
len	TypeError: Object has no len()
list	TypeError: Invalid argument for list()
locals	None
map	TypeError: Function must be callable
max	ValueError: Empty sequence TypeError: Cannot compare different types
memoryview	TypeError: Invalid memory buffer
min	ValueError: Empty sequence TypeError: Cannot compare different types
next	StopIteration: Iterator exhausted TypeError: Object is not an iterator
object	None
oct	TypeError: Object cannot be interpreted as an integer
open	FileNotFoundError: No such file or directory PermissionError: Permission denied IsADirectoryError: Is a directory OSError: Too many open files
ord	TypeError: Argument must be a character ValueError: Character out of range
pow	ZeroDivisionError: 0.0 cannot be raised to a negative power TypeError: Unsupported operand type
print	OSError: Output error
property	None
range	TypeError: Invalid argument type ValueError: Step argument must not be zero
repr	None
reversed	TypeError: Object is not reversible
round	TypeError: Second argument must be an integer
set	TypeError: Invalid argument for set()
setattr	AttributeError: Cannot set attribute TypeError: Invalid attribute name
slice	TypeError: Invalid slice indices
sorted	TypeError: Invalid key function
staticmethod	None
str	TypeError: Invalid type for str()
sum	TypeError: Object in iterable is not summable
super	TypeError: Invalid superclass reference
tuple	TypeError: Invalid argument for tuple()
type	TypeError: Invalid arguments for type()
vars	TypeError: Object must have __dict__ attribute
zip	None

What happens if an error occurs?

When an error occurs due to the configured error probability, an exception will be raised that you can handle with a try-except block. You can ensure that your application is prepared for these errors by adding appropriate error handling.

Contributing

If you want to contribute to the development of MayhemMonkey, you can open a pull request or file an issue on GitHub.

Caveats

Load this as last module, as currently, all imports will fail when this module is loaded.