Minor refactor to support tests and tests added.

    source_proj = f'+proj=cart +a={semi_major} +b={semi_minor}'

    dest_proj = f'+proj=lonlat +a={semi_major} +b={semi_minor}'

    transformer = utils.create_transformer(source_proj, dest_proj)

    while iterations != max_its:

        lon, lat, alt = transformer.transform(intersection.x, 

        lon, lat, _ = transformer.transform(intersection.x, 

                                              intersection.y, 

                                              intersection.z,

                                              errcheck=True)

            raise ValueError(f'No DEM height at {lat}, {lon}')

        next_intersection = camera.imageToGround(image_pt, float(height))

        dist = max(abs(intersection.x - next_intersection.x),

            abs(intersection.y - next_intersection.y),

            abs(intersection.z - next_intersection.z))

        dist = _compute_intersection_distance(intersection, next_intersection)

        intersection = next_intersection

        iterations += 1

            break

    return intersection

def _compute_intersection_distance(intersection, next_intersection):

    """

    Private func that takes two csmapi Ecef objects or other objects with

    x,y,z properties and computes the distance between them. This is the

    maximum distance in 3D space.

    Parameters

    ----------

    intersection : object

                   Any object with x,y, and z properties that are numeric

    next_intersection : object

                        Any object with x,y, and z properties that are numeric              

    Returns

    -------

    dist : float

           The maximum distance between intersection and next_intersection

           in one of the three planes (x,y,z)

    """

    return max(abs(intersection.x - next_intersection.x),

            abs(intersection.y - next_intersection.y),

            abs(intersection.z - next_intersection.z))

def generate_boundary(isize, npoints=10):

    '''

    Generates a bounding box given a camera model

from unittest import mock

import pytest

from plio.io.io_gdal import GeoDataset

import csmapi

from knoten import csm

@pytest.fixture

def mock_dem():

    mock_dem = mock.MagicMock(spec_set=GeoDataset)

    #mock_dem.read_array.return_value = 100

    #mock_dem.latlon_to_pixel.return_value = (0.5,0.5)

    return mock_dem

@pytest.fixture

def mock_sensor():

    mock_sensor = mock.MagicMock(spec=csmapi.RasterGM)

    return mock_sensor

@pytest.fixture

def pt():

    return csmapi.ImageCoord(0.0, 0.0)

def test_generate_ground_point_with_float(mock_sensor):

    csm.generate_ground_point(0, (0.5, 0.5), mock_sensor)

    # The internal conversion from tuple to csmapi.ImageCoord means 

    # assert_called_once_with fails due to different addresses of

    # different objects.

    mock_sensor.imageToGround.assert_called_once()

def test_generate_ground_point_with_imagecoord(mock_sensor, pt):

    height = 0.0

    csm.generate_ground_point(height, pt, mock_sensor)

    mock_sensor.imageToGround.assert_called_once_with(pt, height)

@mock.patch.object(csm, 'get_radii', return_value=(10,10))

@mock.patch('pyproj.transformer.Transformer.transform', return_value=(0,0,0))

@mock.patch.object(csm, '_compute_intersection_distance', return_value=0)

def test_generate_ground_point_with_dtm(mock_dem, mock_sensor, pt):

    # Passing the mock_dem fixture fails for some reason. The

    # isinstance(obj, GeoDataset) check fails, causing the singldispath

    # to never dispatch to the func under test.

    mock_dem = mock.MagicMock(spec_set=GeoDataset)

    mock_dem.no_data_value = 10

    mock_dem.read_array.return_value = [[100]]

    mock_dem.latlon_to_pixel.return_value = (0.5,0.5)

    csm.generate_ground_point(mock_dem, pt, mock_sensor)

    # This call is mocked so that the intitial intersection and 

    # one iteration should occur. Therefore, the call count

    # should always be 2.

    assert mock_sensor.imageToGround.call_count == 2

from collections import namedtuple

@mock.patch.object(csm, 'get_radii', return_value=(10,10))

@mock.patch('pyproj.transformer.Transformer.transform', return_value=(0,0,0))

def test_generate_ground_point_with_dtm_ndv(mock_dem, mock_sensor, pt):

    # Passing the mock_dem fixture fails for some reason. The

    # isinstance(obj, GeoDataset) check fails, causing the singldispath

    # to never dispatch to the func under test.

    mock_dem = mock.MagicMock(spec_set=GeoDataset)

    # If the no data value equals the height, this should raise a value error

    mock_dem.no_data_value = 100

    mock_dem.read_array.return_value = [[100]]

    mock_dem.latlon_to_pixel.return_value = (0.5,0.5)

    with pytest.raises(ValueError):

        csm.generate_ground_point(mock_dem, pt, mock_sensor)

def test__compute_intersection_distance():

    Point = namedtuple("Point", 'x, y, z')

    pt1 = Point(0,0,0)

    pt2 = Point(1,1,1)

    dist = csm._compute_intersection_distance(pt1, pt2)

    assert dist == 1

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