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. Error rate for specific function overrides general error of group
    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.

Functions and 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 Groups and Their Functions

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:

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.