C testing using CFFI, pytest

add.c

#include "add.h"

int add(int a, int b) {
  return a + b;
}

add.h

extern int add(int, int);

test_add.py

import cffi
import importlib
import pytest
import uuid

# taken from https://www.youtube.com/watch?v=zW_HyDTPjO0
def load(filename):
    name = filename + "_" + uuid.uuid4().hex
    
    source = open(filename + ".c").read()
    includes = open(filename + ".h").read()
    
    ffibuilder = cffi.FFI()
    ffibuilder.cdef(includes)
    ffibuilder.set_source(name, source)
    ffibuilder.compile()

    module = importlib.import_module(name)
    return module.lib


addmod = load('add')
def test_add():
    assert addmod.add(12, 13) == 25