def test_flux_remains_constant(self, image_hdu_rect, pixel_scale):
orig_sum = np.sum(image_hdu_rect.data)
new_hdu = imp_utils.rescale_imagehdu(image_hdu_rect,
pixel_scale * u.arcsec.to(u.deg))
new_sum = np.sum(new_hdu.data)
assert new_sum == approx(orig_sum)
def test_mm_flux_remains_constant(self, image_hdu_rect_mm, pixel_scale):
orig_sum = np.sum(image_hdu_rect_mm.data)
new_hdu = imp_utils.rescale_imagehdu(image_hdu_rect_mm,
pixel_scale,
wcs_suffix="D")
new_sum = np.sum(new_hdu.data)
assert new_sum == approx(orig_sum)
def test_rescales_a_2D_imagehdu(self, scale_factor):
hdu0 = imo._image_hdu_rect()
hdu1 = imp_utils.rescale_imagehdu(deepcopy(hdu0), scale_factor / 3600)
hdr0 = hdu0.header
hdr1 = hdu1.header
assert hdr1["NAXIS1"] == np.ceil(hdr0["NAXIS1"] / scale_factor)
assert hdr1["NAXIS2"] == np.ceil(hdr0["NAXIS2"] / scale_factor)
def test_rescales_a_3D_imagehdu(self, scale_factor):
hdu0 = imo._image_hdu_rect()
hdu0.data = hdu0.data[None, :, :] * np.ones(5)[:, None, None]
hdu1 = imp_utils.rescale_imagehdu(deepcopy(hdu0), scale_factor / 3600)
hdr0 = hdu0.header
hdr1 = hdu1.header
assert np.sum(hdu0.data) == approx(np.sum(hdu1.data))
assert hdr1["NAXIS1"] == np.ceil(hdr0["NAXIS1"] / scale_factor)
assert hdr1["NAXIS2"] == np.ceil(hdr0["NAXIS2"] / scale_factor)
assert hdr1["NAXIS3"] == hdr0["NAXIS3"]