Use structured errors from libpolyline

README.md

@@ -39,7 +39,7 @@ decoded_coords = decode_polyline(polyline, 5)
 ```
 
 ## Error Handling
-Failure to encode coordinates, or to decode a supplied Polyline, will raise a `RuntimeError` which can be caught.
+Failure to encode coordinates, or to decode a supplied Polyline, will raise a `RuntimeError` containing information about the invalid input.
 
 
 ## How it Works

src/pypolyline/cutil.pyx

@@ -65,7 +65,7 @@ def encode_coordinates(coords, int precision):
         np.char.startswith(polyline, b"no longitude") or
         np.char.startswith(polyline, b"couldn't")
     ):
-        raise RuntimeError("The input coordinates could not be encoded")
+        raise RuntimeError(polyline)
     return polyline
 
 def decode_polyline(bytes polyline, int precision):

tests/test_pypolyline.py

@@ -49,9 +49,8 @@ def testDecodeBadPolyline(self):
 
     def testEncodeBadCoordinates(self):
         """Test that bad Polylines throw the correct error"""
-        with pytest.raises(RuntimeError) as exc_info:
+        with pytest.raises(RuntimeError) as _:
             cencode_coordinates(self.bad_coordinates, 6)
-        assert str(exc_info.value) == "The input coordinates could not be encoded"
 
     # def testEncodeBadCoordinatesB(self):
     #     """Test that bad Polylines throw the correct error"""