Certain errors not being reported correctly

[tsande01]

parser = argparse.ArgumentParser(description=desc_text)
 parser.add_argument('--some-arg', required=False)

@pyne
def pyne_testing_parsing_test():
   @it("fails when there is an unknown argument")
   def _(self):
      parser.parse(["--some-unknown-argument"]) 

Expected behavior:
the test should fail

Actual behavior:
the error is printed, but the test is not reported as having run.