'Test image data with blank spots in it (which should show up as
NaNs in the data array.'

def test_blanks(self):

    arr = np.zeros((10, 10), dtype=np.int32)
    arr[1] = 999
    hdu = fits.ImageHDU(data=arr)
    hdu.header['BLANK'] = 999
    hdu.writeto(self.temp('test_new.fits'))
    hdul = fits.open(self.temp('test_new.fits'))
    assert np.isnan(hdul[1].data[1]).all()
