Writing unittests

[fractaledmind]

So I'm starting to create unit tests for ZotQuery, and I'm struggling to get alfred-workflow to work with me. While I'm certain to have other issues, my initial problem concerns the assertEqual function within unittest.

Specifically, I can't assertEqual when running a test query through my filter script. Here's my function:

def test_filter(self):
        args = [u'tester', u'general']
        oargs = sys.argv[:]
        sys.argv = [oargs[0]] + [s.encode('utf-8') for s in args]
        xml_res = filter.main(self.wf)
        no_res = """<?xml version="1.0" encoding="utf-8"?>
<items><item valid="no"><title>Error!</title><subtitle>No results found.</subtitle><icon>icons/n_error.png</icon></item></items>"""
        try:
            self.assertEqual(xml_res, no_res)
        finally:
            sys.argv = oargs[:]

When I run filter.main(self.wf), it will print the "No Results" xml to the console, but I can't trap it in a var to assertEqual. How can I write unittests for a workflow written in alfred-workflow?

[deanishe]

Typically, you shouldn't call your main function in unit tests. You should keep it simple and move the functionality to other functions/classes that you call from a barebones main. The general rule is that if you can't isolate a function to unit test it, it isn't designed well and you need to refactor the code anyway.

That won't help you capture the output of Workflow however. To do that you would temporarily reassign sys.stdout (which is what Workflow writes its XML output to) to a StringIO object and read the results from there:

from StringIO import StringIO

fp = StringIO()

# reassign sys.stdout to StringIO instance
orig_stdout = sys.stdout
sys.stdout = fp

# whatever code that makes `Workflow` do its thing here
wf.send_feedback()

# set sys.stdout back to its proper value (a `finally` clause may be a better place for this)
sys.stdout = orig_stdout

# retrieve Workflow output from the StringIO instance
self.assertEqual(fp.getvalue(), expected_value)