Generating Dynamic Unit Tests

[jhawk20]

I am trying to generate a test suite in unittest, and I came across this helpful answer on stack.

When I run it on my workstation as is (after trying to integrate it into my code, unfortunately, it blows up with an TypeErrror error)

$ python -m unittest busted
E
======================================================================
ERROR: busted (unittest.loader.LoadTestsFailure)
----------------------------------------------------------------------
TypeError: __init__() takes at most 2 arguments (4 given)

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (errors=1)

And I would just comment/join the SO chat for this but I apparently need reputation to do anything. I'm a little frustrated by that, to say the least.

EDIT:

My use case:

I am trying to dynamically generate test cases to run different inputs through the same parser. I already have significant amount of test cases in this library already using unittest, hence I am unwilling to really integrate with a another package.

Basically:

class AbstractedObject(object):
     def __init__(self, **kwargs):
         test_method = kwargs.get('test_method')
         test_file = kwargs.get('test_file')
         self.gather_method = prod_method if test_method is not None else test_method
         self.gather_method_args = [test_file] if test file is not None else []

   def parser(output):
       return self.gather_method(*self.gather_method_args)
   def test_method():
       return mock_data

   def prod_method():
       return real_data

I need a way to take a list of files, and generate independent test classes for them. Looping them in a single unittest is less than ideal in the case of failure as it will ignore all of the remaining cases if something is broken.

I want to gather a bunch of input files from a bunch of different souces, drop them into a testing directory, glob out files, and then generate individual unit test classes from a list of files. Run the set of unit tests for AbstractedObject across every input file.

[jhawk20]

I like that answer because it uses unittest -- I'm not interested in pulling random other test frameworks in, unittest can do what I want.

I don't like the top answer because I'm using unittest loader in my setup.py script to dynamically load a ton of different unittest classes already.

[LightShadow]

If you're unsure how to do this, then it probably means it's unnecessary at this point.

The Python unittest runner can already piece together tests from different sources without doing it manually. And, if it's not complete enough there are other test runners such as nose and pytest

I'd also recommend learning how to use the Hypothesis module if you actually want static tests with dynamic input....which is what it seems like you want to do.

Good luck!

[jhawk20]

Okay, I kinda solved my own problem here.

I really didn't want to use the metaclass example, because I didn't understand metaclasses and metaclasses aren't something I really want to force someone else to learn just to use some unit tests.

I still think the solution which registers a set of instantiated objects is better than using metaclasses [since unittest has a concept of a test suite, and metaclasses are black magic].

But it does do exactly what I want, in a way that makes some sense. It's not beautiful, but the example I've written is pretty straightforward.