import numpy as np
from numpy.testing import assert_allclose

import pytest
from pytest import raises

from astropy import units as u

from astropy.wcs import WCS
from astropy.tests.helper import assert_quantity_allclose
from astropy.wcs.wcsapi.utils import deserialize_class, wcs_info_str


def test_construct():

    result = deserialize_class(('astropy.units.Quantity', (10,), {'unit': 'deg'}))
    assert_quantity_allclose(result, 10 * u.deg)


def test_noconstruct():

    result = deserialize_class(('astropy.units.Quantity', (), {'unit': 'deg'}), construct=False)
    assert result == (u.Quantity, (), {'unit': 'deg'})


def test_invalid():

    with raises(ValueError) as exc:
        deserialize_class(('astropy.units.Quantity', (), {'unit': 'deg'}, ()))
    assert exc.value.args[0] == 'Expected a tuple of three values'


DEFAULT_1D_STR = """
WCS Transformation

This transformation has 1 pixel and 1 world dimensions

Array shape (Numpy order): None

Pixel Dim  Axis Name  Data size  Bounds
        0  None            None  None

World Dim  Axis Name  Physical Type  Units
        0  None       None           unknown

Correlation between pixel and world axes:

           Pixel Dim
World Dim    0
        0  yes
"""


def test_wcs_info_str():

    # The tests in test_sliced_low_level_wcs.py excercise wcs_info_str
    # extensively. This test is to ensure that the function exists and the
    # API of the function works as expected.

    wcs_empty = WCS(naxis=1)

    assert wcs_info_str(wcs_empty).strip() == DEFAULT_1D_STR.strip()