test: add test for census field appends

Add test case to verify that all census year fields (census2010,
census2020, census2023, census2024) are properly parsed and included
in the response.

This test currently demonstrates the bug where census2024 and other
years beyond 2023 are not being parsed even though the API returns
them.

Relates to #12

Author: MiniCodeMonkey

tests/unit/test_geocode.py

@@ -498,4 +498,102 @@ def batch_response_callback(request):
     assert resp.results[1].formatted_address == "638 E 13th Ave, Denver, CO 80203"
     assert resp.results[1].fields.timezone.name == "America/Denver"
     assert resp.results[1].fields.timezone.utc_offset == -7
-    assert resp.results[1].fields.congressional_districts[0].district_number == 1
+    assert resp.results[1].fields.congressional_districts[0].district_number == 1
+
+
+def test_geocode_with_census_fields(client, httpx_mock):
+    """Test geocoding with census field appends including all census years."""
+    # Arrange: stub the API call with multiple census years
+    def response_callback(request):
+        assert request.method == "GET"
+        assert request.url.params["fields"] == "census2010,census2020,census2023,census2024"
+        return httpx.Response(200, json={
+            "results": [{
+                "address_components": {
+                    "number": "1640",
+                    "street": "Main",
+                    "suffix": "St",
+                    "city": "Sheldon",
+                    "state": "VT",
+                    "zip": "05483",
+                    "country": "US"
+                },
+                "formatted_address": "1640 Main St, Sheldon, VT 05483",
+                "location": {"lat": 44.895469, "lng": -72.953264},
+                "accuracy": 1,
+                "accuracy_type": "rooftop",
+                "source": "Vermont",
+                "fields": {
+                    "census2010": {
+                        "tract": "960100",
+                        "block": "2001",
+                        "blockgroup": "2",
+                        "county_fips": "50011",
+                        "state_fips": "50"
+                    },
+                    "census2020": {
+                        "tract": "960100",
+                        "block": "2002",
+                        "blockgroup": "2",
+                        "county_fips": "50011",
+                        "state_fips": "50"
+                    },
+                    "census2023": {
+                        "tract": "960100",
+                        "block": "2003",
+                        "blockgroup": "2",
+                        "county_fips": "50011",
+                        "state_fips": "50"
+                    },
+                    "census2024": {
+                        "tract": "960100",
+                        "block": "2004",
+                        "blockgroup": "2",
+                        "county_fips": "50011",
+                        "state_fips": "50"
+                    }
+                }
+            }]
+        })
+
+    httpx_mock.add_callback(
+        callback=response_callback,
+        url=httpx.URL("https://api.test/v1.9/geocode", params={
+            "street": "1640 Main St",
+            "city": "Sheldon",
+            "state": "VT",
+            "postal_code": "05483",
+            "fields": "census2010,census2020,census2023,census2024"
+        }),
+        match_headers={"Authorization": "Bearer TEST_KEY"},
+    )
+
+    # Act
+    resp = client.geocode(
+        {"city": "Sheldon", "state": "VT", "street": "1640 Main St", "postal_code": "05483"},
+        fields=["census2010", "census2020", "census2023", "census2024"],
+    )
+
+    # Assert
+    assert len(resp.results) == 1
+    result = resp.results[0]
+    assert result.formatted_address == "1640 Main St, Sheldon, VT 05483"
+
+    # Check that all census fields are present and parsed correctly
+    assert result.fields.census2010 is not None
+    assert result.fields.census2010.tract == "960100"
+    assert result.fields.census2010.block == "2001"
+    assert result.fields.census2010.county_fips == "50011"
+
+    assert result.fields.census2020 is not None
+    assert result.fields.census2020.tract == "960100"
+    assert result.fields.census2020.block == "2002"
+
+    assert result.fields.census2023 is not None
+    assert result.fields.census2023.tract == "960100"
+    assert result.fields.census2023.block == "2003"
+
+    # This will fail until we fix the parsing logic
+    assert result.fields.census2024 is not None
+    assert result.fields.census2024.tract == "960100"
+    assert result.fields.census2024.block == "2004"