/django/contrib/gis/geometry/test_data.py

"""
This module has the mock object definitions used to hold reference geometry
for the GEOS and GDAL tests.
"""
import gzip
import os

from django.contrib import gis
from django.utils import simplejson


# This global used to store reference geometry data.
GEOMETRIES = None

# Path where reference test data is located.
TEST_DATA = os.path.join(os.path.dirname(gis.__file__), 'tests', 'data')


def tuplize(seq):
    "Turn all nested sequences to tuples in given sequence."
    if isinstance(seq, (list, tuple)):
        return tuple([tuplize(i) for i in seq])
    return seq


def strconvert(d):
    "Converts all keys in dictionary to str type."
    return dict([(str(k), v) for k, v in d.iteritems()])


def get_ds_file(name, ext):
    return os.path.join(TEST_DATA,
                        name,
                        name + '.%s' % ext
                        )


class TestObj(object):
    """
    Base testing object, turns keyword args into attributes.
    """
    def __init__(self, **kwargs):
        for key, value in kwargs.items():
            setattr(self, key, value)


class TestDS(TestObj):
    """
    Object for testing GDAL data sources.
    """
    def __init__(self, name, **kwargs):
        # Shapefile is default extension, unless specified otherwise.
        ext = kwargs.pop('ext', 'shp')
        self.ds = get_ds_file(name, ext)
        super(TestDS, self).__init__(**kwargs)


class TestGeom(TestObj):
    """
    Testing object used for wrapping reference geometry data
    in GEOS/GDAL tests.
    """
    def __init__(self, **kwargs):
        # Converting lists to tuples of certain keyword args
        # so coordinate test cases will match (JSON has no
        # concept of tuple).
        coords = kwargs.pop('coords', None)
        if coords:
            self.coords = tuplize(coords)

        centroid = kwargs.pop('centroid', None)
        if centroid:
            self.centroid = tuple(centroid)

        ext_ring_cs = kwargs.pop('ext_ring_cs', None)
        if ext_ring_cs:
            ext_ring_cs = tuplize(ext_ring_cs)
        self.ext_ring_cs = ext_ring_cs

        super(TestGeom, self).__init__(**kwargs)


class TestGeomSet(object):
    """
    Each attribute of this object is a list of `TestGeom` instances.
    """
    def __init__(self, **kwargs):
        for key, value in kwargs.items():
            setattr(self, key, [TestGeom(**strconvert(kw)) for kw in value])


class TestDataMixin(object):
    """
    Mixin used for GEOS/GDAL test cases that defines a `geometries`
    property, which returns and/or loads the reference geometry data.
    """
    @property
    def geometries(self):
        global GEOMETRIES
        if GEOMETRIES is None:
            # Load up the test geometry data from fixture into global.
            gzf = gzip.GzipFile(os.path.join(TEST_DATA, 'geometries.json.gz'))
            geometries = simplejson.loads(gzf.read())
            GEOMETRIES = TestGeomSet(**strconvert(geometries))
        return GEOMETRIES