pytest capture bug

conftest.py

# if you uncomment this, the test works as expected
import dummy

dummy.cpp

#include <Python.h>
#include <iostream>

static PyMethodDef dummy_methods[] = {
	{NULL, NULL, 0, NULL}
};


PyMODINIT_FUNC initdummy(void) {
	PyObject* dummy_module = Py_InitModule3("dummy", dummy_methods,
                                            "dummy module");

    // if you comment out this, test_noflush works as expected
    std::cout << "Initialising dummy..." << std::endl;
}

setup.py

from setuptools import setup, Extension

setup(
    name="dummy",
    ext_modules = [Extension('dummy', ['dummy.cpp'])],
)

test_noflush.py

import sys
import time

def test_noflush(capfd):
    with capfd.disabled():
        for i in range(10):
            sys.stdout.write('%d\n' % i)
            # if you uncomment this, you can see the output again
            #sys.stdout.flush()
            time.sleep(0.2)


def test_enter_pdb():
    0/0