Question

I wrote a python module. Running python filename.py, only checks for syntax errors. Is there a tool, which checks for runtime errors also, like concatenating int with string etc..

Thank you
Bala

Update:
Scripts are mainly about setting up a hadoop cluster in the cloud. I am not sure how I can write a unit test, because everything runs in the cloud. You can think of code as legacy code, and I just added more logging and some extra conditions a few places

Answer 1

Traditionally, if not writing full-fledged unit-tests and/or doc-tests (writing lots of tests is of course best practice!), one at least puts in every module a def main(): function to exercise it and ends the module with

if __name__ == '__main__':
  main()

so main() won’t get in the way if the module’s just imported, but it will execute if you run the module as your main script. Of course, you need to actually exercise the code in the module from within main(), for this to catch all kinds of semantic problems such as the type error you mention — doing a really thorough job this way is often as hard as writing real unit tests and doc tests would be, but you can at least get started!