CODEWITHSUNDEEP
pythonunit-testingiostdin
Brian Peterson
Brian Peterson

Reputation: 2998

How do I write a test for an interactive text-based program?

I'm trying to write a test (using unittest) for a simple Python program. It is an interactive program, specifcally it will be a text-based game, for now basically a port of World of Zuul to Python.

So now I want to do good test-driven development and write a test and make sure that when the user inputs command x, that y results happen. Example: when the user inputs "quit", I want the program to end. I want to ensure that behavior. The only problem is, I can't seem to think of a way to give my own program input without actually typing that input into the shell, so I can't think of how to write a test for this.

Currently, I have embedded the program in its own thread... I was thinking this would allow me to asynchronously give it input, but I still don't see how this can be done.

Is there a way to programmatically and dynamically give my own program input? ... Like, using stdin or something? If so I am thoroughly confused, and would appreciate an example.

Finally, if I am on the wrong track here, please tell me, because I am new to both Python and test-driven development, and I would appreciate any suggestions.

Upvotes: 1

Views: 740

Answers (1)

Fred Foo
Fred Foo

Reputation: 363607

You can set up tests that run the program's main function and read the input that the user would provide from a file (or from a string) if you set up the code like this:

def main(inp):
    # play game

if __name__ == '__main__':
    main(sys.stdin)

Then the test involves setting up an input stream (perhaps a StringIO), feeding that to main, and monitoring the output. If you think the program might hang, you can run it in a separate thread and give it a timeout.

If you want to get fancy, you can even use a pty to simulate terminal input.

Upvotes: 1

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