Explicit key_of_x check in Choropleth (#1169)

Add explicit check for None in color_scale_fun(x) from class Choropleth. Add test.

Author: LeandroOrdonez

folium/features.py

@@ -1109,7 +1109,7 @@ def get_by_key(obj, key):
 
             def color_scale_fun(x):
                 key_of_x = get_by_key(x, key_on)
-                if not key_of_x:
+                if key_of_x is None:
                     raise ValueError("key_on `{!r}` not found in GeoJSON.".format(key_on))
 
                 if key_of_x not in color_data.keys():

tests/geo_grid.json

@@ -0,0 +1,8 @@
+{"type": "FeatureCollection", "features": [
+{"id": "0", "type": "Feature", "properties": {"idx": 0}, "geometry": {"type": "Polygon", "coordinates": [[[479978.6866107661, 6676603.690234357], [491978.6866107661, 6676603.690234357], [491978.6866107661, 6664603.690234357], [479978.6866107661, 6664603.690234357], [479978.6866107661, 6676603.690234357]]]}}, 
+{"id": "1", "type": "Feature", "properties": {"idx": 1}, "geometry": {"type": "Polygon", "coordinates": [[[479978.6866107661, 6664603.690234357], [491978.6866107661, 6664603.690234357], [491978.6866107661, 6652603.690234357], [479978.6866107661, 6652603.690234357], [479978.6866107661, 6664603.690234357]]]}}, 
+{"id": "2", "type": "Feature", "properties": {"idx": 2}, "geometry": {"type": "Polygon", "coordinates": [[[479978.6866107661, 6652603.690234357], [491978.6866107661, 6652603.690234357], [491978.6866107661, 6640603.690234357], [479978.6866107661, 6640603.690234357], [479978.6866107661, 6652603.690234357]]]}}, 
+{"id": "3", "type": "Feature", "properties": {"idx": 3}, "geometry": {"type": "Polygon", "coordinates": [[[491978.6866107661, 6676603.690234357], [503978.6866107661, 6676603.690234357], [503978.6866107661, 6664603.690234357], [491978.6866107661, 6664603.690234357], [491978.6866107661, 6676603.690234357]]]}}, 
+{"id": "4", "type": "Feature", "properties": {"idx": 4}, "geometry": {"type": "Polygon", "coordinates": [[[491978.6866107661, 6664603.690234357], [503978.6866107661, 6664603.690234357], [503978.6866107661, 6652603.690234357], [491978.6866107661, 6652603.690234357], [491978.6866107661, 6664603.690234357]]]}}, 
+{"id": "5", "type": "Feature", "properties": {"idx": 5}, "geometry": {"type": "Polygon", "coordinates": [[[491978.6866107661, 6652603.690234357], [503978.6866107661, 6652603.690234357], [503978.6866107661, 6640603.690234357], [491978.6866107661, 6640603.690234357], [491978.6866107661, 6652603.690234357]]]}}
+]}

tests/test_folium.py

@@ -230,6 +230,26 @@ def test_choropleth_features(self):
         assert '"fillColor":"a_random_color","fillOpacity":0.123454321' in out_str
         assert '"fillOpacity":0.543212345' in out_str
 
+    def test_choropleth_key_on(self):
+        """Test to make sure that Choropleth function doesn't raises
+        a ValueError when the 'key_on' field is set to a column that might
+        have 0 as a value.
+        """
+        with open(os.path.join(rootpath, 'geo_grid.json')) as f:
+            geo_data = json.load(f)
+        data = pd.DataFrame({'idx': {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5},
+                             'value': {'0': 78.0, '1': 39.0, '2': 0.0, '3': 81.0, '4': 42.0, '5': 68.0}})
+        fill_color = 'BuPu'
+        columns = ['idx', 'value']
+        key_on = 'feature.properties.idx'
+
+        Choropleth(
+            geo_data=geo_data,
+            data=data,
+            key_on=key_on,
+            fill_color=fill_color,
+            columns=columns)
+
     def test_choropleth_warning(self):
         """Test that the Map.choropleth method works and raises a warning."""
         self.setup()