python, unittest: is there a way to pass command line options to the app

I have a module that imports unittest and has some TestCases. I would like to accept some command-line options (for example below, the name of a data file), but when I try to pass the option I get the message option -i not recognized. Is it possible to have unittest + provide options to the app (note: I'm using optparse to handle the options)? Thanks.

$ python test_app_data.py -i data_1.txt

option -i not recognized

=====================

follow-up: this is an implementation of the suggested solution:

import cfg_master  #has the optparse option-handling code

...

if __name__ == '__main__':    
    #add you app's options here...
    options_tpl = ('-i', '--in_dir', '-o', '--out_dir')
    del_lst = []
    for i,option in enumerate(sys.argv):
        if option in options_tpl:
            del_lst.append(i)
            del_lst.append(i+1)

    del_lst.reverse()
    for i in del_lst:
        del sys.argv[i]
        
    unittest.main()

Building on Alex's answer, it's actually pretty easy to do using argparse:

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--input', default='My Input')
    parser.add_argument('filename', default='some_file.txt')
    parser.add_argument('unittest_args', nargs='*')

    args = parser.parse_args()
    # TODO: Go do something with args.input and args.filename

    # Now set the sys.argv to the unittest_args (leaving sys.argv[0] alone)
    sys.argv[1:] = args.unittest_args
    unittest.main()

I haven't tested all of the flags you can pass into unittest to see if they work or not, but passing test names in does work, e.g.:

python test.py --input=foo data.txt MyTest

Runs MyTest with foo and data.txt.

In your if __name__ == '__main__': section, which you're not showing us, you'll need to optparse and then del sys.argv[1:] before you pass control to unittest code, so that the latter code doesn't try to interpret your command line options again when you've already dealt with them. (It's a bit harder to have some options of your own and also pass some down to unittest, though it can be done if you do have such complex needs).