Interactive testing

[LeMinaw]

Here is a quick PoC of how we could test the CLI. It basically runs an async child process.

Some more work is still needed to integrate it nicely with pytest, but it should be quite straightforward.

story.py

This is the program we are testing. It prompts for some values in a random order, then returns a string out of it.

from random import shuffle


prompts = ["name", "color", "year"]


if __name__ == '__main__':
    shuffle(prompts)
    data = {prompt: input(f"{prompt}: ") for prompt in prompts}
    print(
        "By the time, {name} liked {color}. The year was {year}."
        .format(**data)
    )

tester.py

This program is testing story.py.

import asyncio as aio


BUF_SIZE = 0x400

DATA = {
    "name: ": "Clara",
    "color: ": "red",
    "year: ": 1777,
}

RESULT = "By the time, Clara liked red. The year was 1777.\r\n"


async def test():
    sp = await aio.subprocess.create_subprocess_exec(
        "python", "./story.py",
        stdin=aio.subprocess.PIPE,
        stdout=aio.subprocess.PIPE,
    )

    while True:
        out = (await sp.stdout.read(BUF_SIZE)).decode()

        if out in DATA:
            sp.stdin.write(f"{DATA[out]}\n".encode())
        else:
            assert out == RESULT
            break            
    
    retcode = await sp.wait()
    assert not retcode

if __name__ == '__main__':
    aio.run(test())
    print("Testing done.")

[LeMinaw]

This is being worked on in #43 using a different approach, more integrated to click