Test Shapely with MongoDB GeoJSON examples

test_mongodb_examples.py

#!/usr/bin/env python
# -*- coding: utf-8 -*


import pytest
import typing as typ
import pymongo as pm
import mongoengine as me
import shapely.geometry as geo


GEOMETRIES = [
    pytest.param(
        {
            'type': "Point",
            'coordinates': [40.0, 5.0]
        },
        id="a GeoJSON Point"
    ),
    pytest.param(
        {
            'type': "LineString",
            'coordinates': [[40.0, 5.0], [41.0, 6.0]]
        },
        id="a GeoJSON LineString"
    ),
    pytest.param(
        {
            'type': "Polygon",
            'coordinates': [
                [[0.0, 0.0], [3.0, 6.0], [6.0, 1.0], [0.0, 0.0]]
            ]
        },
        id="a GeoJSON Polygon with a single ring"
    ),
    pytest.param(
        {
            'type': "Polygon",
            'coordinates': [
                [[0.0, 0.0], [3.0, 6.0], [6.0, 1.0], [0.0, 0.0]],
                [[2.0, 2.0], [3.0, 3.0], [4.0, 2.0], [2.0, 2.0]]
            ]
        },
        id="a GeoJSON Polygon with multiple rings"
    ),
    pytest.param(
        {
            'type': "MultiPoint",
            'coordinates': [
                [-73.9580, 40.8003],
                [-73.9498, 40.7968],
                [-73.9737, 40.7648],
                [-73.9814, 40.7681]
            ]
        },
        id="a GeoJSON MultiPoint"
    ),
    pytest.param(
        {
            'type': "MultiLineString",
            'coordinates': [
                [[-73.96943, 40.78519], [-73.96082, 40.78095]],
                [[-73.96415, 40.79229], [-73.95544, 40.78854]],
                [[-73.97162, 40.78205], [-73.96374, 40.77715]],
                [[-73.97880, 40.77247], [-73.97036, 40.76811]]
            ]
        },
        id="a GeoJSON MultiLineString"
    ),
    pytest.param(
        {
            'type': "MultiPolygon",
            'coordinates': [
                [[[-73.958, 40.8003], [-73.9498, 40.7968], [-73.9737, 40.7648], [-73.9814, 40.7681], [-73.958, 40.8003]]],
                [[[-73.958, 40.8003], [-73.9498, 40.7968], [-73.9737, 40.7648], [-73.958, 40.8003]]]
            ]
        },
        id="a GeoJSON MultiPolygon",
        marks=pytest.mark.xfail(
            raises=AssertionError,
            reason="MultiPolygon has polygon intersection"
        )
    ),
    pytest.param(
        {
            'type': "GeometryCollection",
            'geometries': [
                {
                    'type': "MultiPoint",
                    'coordinates': [
                        [-73.9580, 40.8003],
                        [-73.9498, 40.7968],
                        [-73.9737, 40.7648],
                        [-73.9814, 40.7681]
                    ]
                },
                {
                    'type': "MultiLineString",
                    'coordinates': [
                        [[-73.96943, 40.78519], [-73.96082, 40.78095]],
                        [[-73.96415, 40.79229], [-73.95544, 40.78854]],
                        [[-73.97162, 40.78205], [-73.96374, 40.77715]],
                        [[-73.97880, 40.77247], [-73.97036, 40.76811]]
                    ]
                }
            ]
        },
        id="a GeoJSON GeometryCollection",
        marks=pytest.mark.xfail(
            raises=AttributeError,
            reason="MongoEngine has no a GeometryCollectionField"
        )
    )
]


GeoJSON = typ.Dict[str, typ.Any]


@pytest.fixture
def query() -> GeoJSON:
    return {
        'type': "Polygon",
        'coordinates': [
            [[-179, -89], [180, -89], [180, 90], [-179, 90], [-179, -89]]
        ]
    }


@pytest.mark.parametrize('value', GEOMETRIES)
def test_shape_from_geojson(value: GeoJSON, query: GeoJSON):
    """
    Using sample GeoJSON-like dictionaries from MongoDB GeoJSON examples_,
    test, using Shapley_, by:

     - interpret GeoJSON data as Shapely geometry
     - assert geometry conforms to OpenGIS standards_
     - convert Shapely geometry back to GeoJSON data
     - assert original and converted GeoJSON consistent
     - retrieve the MongoEngine field type matching the geometry
     - connect to MongoDB and register 'tmpdb' with MongoEngine
     - drop document collection if it exists
     - define a document with matching GeoJSON field type
     - store the mapped GeoJSON data in the field values
     - validate the document
     - save the document to MongoDB
     - assert collection exists after save
     - assert saved field value matches GeoJSON data
     - query collection with huge Polygon
     - assert document found from query
     - drop document collection
     - assert document collection does not exist

    .. _examples: https://docs.mongodb.com/manual/reference/geojson/
    .. _Shapley: http://toblerity.org/shapely/
    .. _standards: http://www.opengeospatial.org/standards/sfa

    :param value: GeoJSON feature to store
    :param query: GeoJSON Polygon to query with
    """

    shape = geo.shape(value)

    assert shape.is_valid, "shape failed OpenGIS validation"

    mapped = geo.mapping(shape)

    # NOTE 'mapping` uses tuples, BSON/JSON uses lists
    # assert mapped == value, "mapped value does not match original"

    field = getattr(me, "{:s}Field".format(value['type']))

    cc = me.connect('tmpdb')  # type: pm.MongoClient
    db = cc.get_database('tmpdb')

    if 'doc' in db.list_collection_names():
        db.drop_collection('doc')
        assert 'doc' not in db.list_collection_names(), "collection should not exist after drop"

    class Doc(me.Document):
        value = field()
        query = me.PolygonField()

    doc = Doc()
    doc.value = mapped
    doc.query = query
    doc.validate()
    doc.save()

    assert 'doc' in db.list_collection_names(), "expected collection to exist after save"

    assert Doc.objects[0].value == value, "value from mongo does not match original"

    qry = Doc.objects(value__geo_within=doc.query)  # type: me.QuerySet

    assert qry.first() is not None, "expected successful query"

    Doc.drop_collection()

    assert 'doc' not in db.list_collection_names(), "failed to drop collection"