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import os
import mapnik
import pytest
from .utilities import execution_path
@pytest.fixture(scope="module")
def setup():
# All of the paths used are relative, if we run the tests
# from another directory we need to chdir()
os.chdir(execution_path('.'))
yield
def test_adding_datasource_to_layer(setup):
if not os.path.exists('../data/shp/world_merc.shp'):
pytest.skip('Missing data')
map_string = '''<?xml version="1.0" encoding="utf-8"?>
<Map>
<Layer name="world_borders">
<StyleName>world_borders_style</StyleName>
<StyleName>point_style</StyleName>
<!-- leave datasource empty -->
<!--
<Datasource>
<Parameter name="file">../data/shp/world_merc.shp</Parameter>
<Parameter name="type">shape</Parameter>
</Datasource>
-->
</Layer>
</Map>
'''
m = mapnik.Map(256, 256)
try:
mapnik.load_map_from_string(m, map_string)
# validate it loaded fine
assert m.layers[0].styles[0] == 'world_borders_style'
assert m.layers[0].styles[1] == 'point_style'
assert len(m.layers) == 1
# also assign a variable reference to that layer
# below we will test that this variable references
# the same object that is attached to the map
lyr = m.layers[0]
# ensure that there was no datasource for the layer...
assert m.layers[0].datasource == None
assert lyr.datasource == None
# also note that since the srs was black it defaulted to wgs84
assert m.layers[0].srs == 'epsg:4326'
assert lyr.srs == 'epsg:4326'
# now add a datasource one...
ds = mapnik.Shapefile(file='../data/shp/world_merc.shp')
m.layers[0].datasource = ds
# now ensure it is attached
assert m.layers[0].datasource.describe()['name'] == "shape"
assert lyr.datasource.describe()['name'] == "shape"
# and since we have now added a shapefile in spherical mercator, adjust
# the projection
lyr.srs = '+proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs'
# test that assignment
assert m.layers[0].srs == '+proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs'
assert lyr.srs == '+proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs'
except RuntimeError as e:
# only test datasources that we have installed
if not 'Could not create datasource' in str(e):
raise RuntimeError(e)
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