def _setDefaults(configObj={}):
    """set up the default parameters to run drizzle
       build,single,units,wt_scl,pixfrac,kernel,fillval,
       rot,scale,xsh,ysh,blotnx,blotny,outnx,outny,data

       Used exclusively for unit-testing, if any are defined.

    """
    paramDict = {'build': True, 'single': True, 'stepsize': 10, 'in_units':
        'cps', 'wt_scl': 1.0, 'pixfrac': 1.0, 'kernel': 'square', 'fillval':
        999.0, 'maskval': None, 'rot': 0.0, 'scale': 1.0, 'xsh': 0.0, 'ysh':
        0.0, 'blotnx': 2048, 'blotny': 2048, 'outnx': 4096, 'outny': 4096,
        'data': None, 'driz_separate': True, 'driz_combine': False}
    if len(configObj) != 0:
        for key in configObj.keys():
            paramDict[key] = configObj[key]
    return paramDict
