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"""
Test cases for Voronoi Diagram creation.
Overall, I'm trying less to test the correctness of the result
and more to cover input cases and behavior, making sure
that we return a sane result without error or raise a useful one.
"""
import numpy as np
import pytest
from shapely.geometry import MultiPoint
from shapely.ops import voronoi_diagram
from shapely.wkt import loads as load_wkt
def test_no_regions():
mp = MultiPoint(points=[(0.5, 0.5)])
with np.errstate(invalid="ignore"):
regions = voronoi_diagram(mp)
assert len(regions.geoms) == 0
def test_two_regions():
mp = MultiPoint(points=[(0.5, 0.5), (1.0, 1.0)])
regions = voronoi_diagram(mp)
assert len(regions.geoms) == 2
def test_edges():
mp = MultiPoint(points=[(0.5, 0.5), (1.0, 1.0)])
regions = voronoi_diagram(mp, edges=True)
assert len(regions.geoms) == 1
# can be LineString or MultiLineString depending on the GEOS version
assert all(r.geom_type.endswith("LineString") for r in regions.geoms)
def test_smaller_envelope():
mp = MultiPoint(points=[(0.5, 0.5), (1.0, 1.0)])
poly = load_wkt("POLYGON ((0 0, 0.5 0, 0.5 0.5, 0 0.5, 0 0))")
regions = voronoi_diagram(mp, envelope=poly)
assert len(regions.geoms) == 2
assert sum(r.area for r in regions.geoms) > poly.area
def test_larger_envelope():
"""When the envelope we specify is larger than the
area of the input feature, the created regions should
expand to fill that area."""
mp = MultiPoint(points=[(0.5, 0.5), (1.0, 1.0)])
poly = load_wkt("POLYGON ((0 0, 2 0, 2 2, 0 2, 0 0))")
regions = voronoi_diagram(mp, envelope=poly)
assert len(regions.geoms) == 2
assert sum(r.area for r in regions.geoms) == poly.area
def test_from_polygon():
poly = load_wkt("POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))")
regions = voronoi_diagram(poly)
assert len(regions.geoms) == 4
def test_from_polygon_with_enough_tolerance():
poly = load_wkt("POLYGON ((0 0, 0.5 0, 0.5 0.5, 0 0.5, 0 0))")
regions = voronoi_diagram(poly, tolerance=1.0)
assert len(regions.geoms) == 2
def test_from_polygon_without_enough_tolerance():
poly = load_wkt("POLYGON ((0 0, 0.5 0, 0.5 0.5, 0 0.5, 0 0))")
with pytest.raises(ValueError) as exc:
voronoi_diagram(poly, tolerance=0.6)
assert "Could not create Voronoi Diagram with the specified inputs" in str(
exc.value
)
assert "Try running again with default tolerance value." in str(exc.value)
def test_from_polygon_without_floating_point_coordinates():
poly = load_wkt("POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))")
with pytest.raises(ValueError) as exc:
voronoi_diagram(poly, tolerance=0.1)
assert "Could not create Voronoi Diagram with the specified inputs" in str(
exc.value
)
assert "Try running again with default tolerance value." in str(exc.value)
def test_from_multipoint_without_floating_point_coordinates():
"""A Multipoint with the same "shape" as the above Polygon raises the same error."""
mp = load_wkt("MULTIPOINT (0 0, 1 0, 1 1, 0 1)")
with pytest.raises(ValueError) as exc:
voronoi_diagram(mp, tolerance=0.1)
assert "Could not create Voronoi Diagram with the specified inputs" in str(
exc.value
)
assert "Try running again with default tolerance value." in str(exc.value)
def test_from_multipoint_with_tolerace_without_floating_point_coordinates():
"""This multipoint will not work with a tolerance value."""
mp = load_wkt("MULTIPOINT (0 0, 1 0, 1 2, 0 1)")
with pytest.raises(ValueError) as exc:
voronoi_diagram(mp, tolerance=0.1)
assert "Could not create Voronoi Diagram with the specified inputs" in str(
exc.value
)
assert "Try running again with default tolerance value." in str(exc.value)
def test_from_multipoint_without_tolerace_without_floating_point_coordinates():
"""But it's fine without it."""
mp = load_wkt("MULTIPOINT (0 0, 1 0, 1 2, 0 1)")
regions = voronoi_diagram(mp)
assert len(regions.geoms) == 4
|
