'Test setting the field_specifier attribute and updating the card image
to reflect the new value.'

def test_update_field_specifier(self):

    c = fits.Card.fromstring("DP1                    =    'NAXIS:    2'    /    A    comment")
    assert (c.field_specifier == 'NAXIS')
    c.field_specifier = 'NAXIS1'
    assert (c.field_specifier == 'NAXIS1')
    assert (c.keyword == 'DP1.NAXIS1')
    assert (c.value == 2.0)
    assert (c.comment == 'A    comment')
    assert (str(c).rstrip() == "DP1                    =    'NAXIS1:    2'    /    A    comment")
