Add tests and safety to exterior.

Author: eseglem

geojson_pydantic/geometries.py

@@ -159,9 +159,9 @@ def check_closure(cls, coordinates: List) -> List:
         return coordinates
 
     @property
-    def exterior(self) -> LinearRing:
+    def exterior(self) -> Union[LinearRing, None]:
         """Return the exterior Linear Ring of the polygon."""
-        return self.coordinates[0]
+        return self.coordinates[0] if self.coordinates else None
 
     @property
     def interiors(self) -> Iterator[LinearRing]:
@@ -250,7 +250,11 @@ def _wkt_coordinates(self) -> str:
     @property
     def wkt(self) -> str:
         """Return the Well Known Text representation."""
-        return f"{self._wkt_type} ({self._wkt_coordinates})"
+        return (
+            self._wkt_type
+            + " "
+            + (f"({self._wkt_coordinates})" if self._wkt_coordinates else "EMPTY")
+        )
 
     @property
     def __geo_interface__(self) -> Dict[str, Any]:

tests/test_geometries.py

@@ -175,6 +175,8 @@ def test_polygon_valid_coordinates(coordinates):
     assert hasattr(polygon, "__geo_interface__")
     if polygon.coordinates:
         assert polygon.exterior == coordinates[0]
+    else:
+        assert polygon.exterior is None
     assert not list(polygon.interiors)
     assert_wkt_equivalence(polygon)
 
@@ -468,3 +470,22 @@ class PointType(Point):
         PointType(type="Point", coordinates=(1.01, 2.01)).wkt
         == Point(type="Point", coordinates=(1.01, 2.01)).wkt
     )
+
+
+@pytest.mark.parametrize(
+    "shape",
+    [
+        MultiPoint,
+        MultiLineString,
+        Polygon,
+        MultiPolygon,
+    ],
+)
+def test_wkt_empty(shape):
+    assert shape(type=shape.__name__, coordinates=[]).wkt.endswith(" EMPTY")
+
+
+def test_wkt_empty_geometrycollection():
+    assert GeometryCollection(type="GeometryCollection", geometries=[]).wkt.endswith(
+        " EMPTY"
+    )