def METHOD_NAME(self):
    """Test creation of fibermaps with missing input columns"""
    #- second exposure of split, missing fiber location information
    #- in coordinates file, but info is present in previous exposure
    #- that was same tile and first in sequence
    fm1 = assemble_fibermap(20210406, 83714)['FIBERMAP'].data
    fm2 = assemble_fibermap(20210406, 83715)['FIBERMAP'].data
    def nanequal(a, b):
        """Compare two arrays treating NaN==NaN"""
        return np.equal(a, b, where=~np.isnan(a))
    assert np.all(nanequal(fm1['FIBER_X'], fm2['FIBER_X']))
    assert np.all(nanequal(fm1['FIBER_Y'], fm2['FIBER_Y']))
    assert np.all(nanequal(fm1['FIBER_RA'], fm2['FIBER_RA']))
    assert np.all(nanequal(fm1['FIBER_DEC'], fm2['FIBER_DEC']))
    assert np.all(nanequal(fm1['DELTA_X'], fm2['DELTA_X']))
    assert np.all(nanequal(fm1['DELTA_Y'], fm2['DELTA_Y']))