如何编写测试我的c ++的python脚本？

Question

Say I wanna test my c++ code but I don't want to do it by hand. I realize I can write a python script that can test my code for me. So I want to test this c++ code for example:

#include <iostream>
#include <string>
using namespace std;

int main() {
   string line;
   cin >> line;
   cout << line << endl;
}

Here is the python script that I tried to test this c++ code:

import subprocess as sb

sb.call("g++ main.cpp", shell=True)
sb.call("./a.out", shell=True)
sb.call("chocolate", shell=True)

This create the a.out executable file but it doesn't allow me to run my program. How can I make this work? Or is there something better that I can do?

Answer 1

Testing can get complicated but as a minimum you can use the subprocess.Popen object to manage the input and output of the program. Here is a minimalist test suite

import subprocess as sb
import threading

def timeout():
    print('timeout')
    exit(3)

sb.check_call("g++ main.cpp", shell=True)
t = threading.Timer(10, timeout)
proc = sb.Popen("./a.out", shell=True, stdin=sb.PIPE, stdout=sb.PIPE,
    stderr=sb.PIPE)
out, err = proc.communicate('hello\n')
t.cancel()
assert proc.returncode == 0
assert out == 'hello\n'
assert err == ''
sb.check_call("chocolate", shell=True)