def test_array_option_empty_equivalents(self):
        """Array options treat -Dopt=[] and -Dopt= as equivalent."""
        def get_opt():
            opts = self.introspect('--buildoptions')
            for x in opts:
                if x.get('name') == 'list':
                    return x
            raise Exception(opts)

        expected = {
            'name': 'list',
            'description': 'list',
            'section': 'user',
            'type': 'array',
            'value': [],
            'choices': ['foo', 'bar', 'oink', 'boink'],
            'machine': 'any',
        }
        tdir = os.path.join(self.unit_test_dir, '19 array option')
        self.init(tdir, extra_args='-Dlist=')
        original = get_opt()
        self.assertDictEqual(original, expected)
Array options treat -Dopt=[] and -Dopt= as equivalent.
unittests/allplatformstests.py