Bug/fix serialisation reforecast data

covjsonkit/encoder/encoder.py

@@ -3,6 +3,7 @@
 from abc import ABC, abstractmethod
 from typing import Any
 
+import numpy as np
 import orjson
 import pandas as pd
 from covjson_pydantic.coverage import CoverageCollection
@@ -176,7 +177,10 @@ def create_composite_key(date, level, num, para, s):
         def handle_non_leaf_node(child):
             non_leaf_axes = ["latitude", "longitude", "param", date_key]
             if child.axis.name not in non_leaf_axes:
-                mars_metadata[child.axis.name] = child.values[0]
+                val = child.values[0]
+                if isinstance(val, np.datetime64):
+                    val = str(val)
+                mars_metadata[child.axis.name] = val
 
         def handle_specific_axes(child):
             if child.axis.name == "latitude":
@@ -272,7 +276,10 @@ def create_composite_key_step(date, level, num, para):
         def handle_non_leaf_node_step(child):
             non_leaf_axes = ["latitude", "longitude", "param", "date", "time"]
             if child.axis.name not in non_leaf_axes:
-                mars_metadata[child.axis.name] = child.values[0]
+                val = child.values[0]
+                if isinstance(val, np.datetime64):
+                    val = str(val)
+                mars_metadata[child.axis.name] = val
 
         def handle_specific_axes_step(child):
             if child.axis.name == "latitude":
@@ -441,7 +448,10 @@ def _ensure_date_keys():
         def handle_non_leaf_node_month(child):
             non_leaf_axes = ["latitude", "longitude", "param", "year", "month"]
             if child.axis.name not in non_leaf_axes:
-                mars_metadata[child.axis.name] = child.values[0]
+                val = child.values[0]
+                if isinstance(val, np.datetime64):
+                    val = str(val)
+                mars_metadata[child.axis.name] = val
 
         def handle_specific_axes_month(child):
             if child.axis.name == "latitude":

covjsonkit/version.py

@@ -1 +1 @@
-__version__ = "0.2.16"
+__version__ = "0.2.17"

pyproject.toml

@@ -8,7 +8,7 @@ markers = ["data: uses test data (deselect with '-m \"not data\"')",]
 
 [project]
 name = "covjsonkit"
-version = "0.2.16"
+version = "0.2.17"
 dependencies = [
     "pandas<3",
     "orjson",

tests/conftest.py

@@ -6,7 +6,7 @@
 
 REFORECAST_METADATA_BASE = {
     "class": "ce",
-    "date": np.datetime64("2024-03-01"),
+    "date": "2024-03-01",
     "domain": "g",
     "expver": "4321",
     "levtype": "sfc",

tests/geojsontest.py

@@ -0,0 +1,16 @@
+import json
+import os
+
+from covjsonkit.api import Covjsonkit
+
+current_dir = os.path.dirname(__file__)
+timeseries = os.path.join(current_dir, "data/test_timeseries_coverage.json")
+with open(timeseries, "r") as f:
+    timeseries = json.load(f)
+
+
+cov = Covjsonkit().decode(timeseries)
+ts = cov.to_geojson()
+print(ts)
+assert ts["type"] == "FeatureCollection"
+assert len(ts["features"]) == 16

tests/test_encoder_bounding_box_from_polytope.py

@@ -22,7 +22,7 @@
 
 EXPECTED_REFORECAST_METADATA = {
     "class": "ce",
-    "date": np.datetime64("2024-03-01"),
+    "date": "2024-03-01",
     "domain": "g",
     "expver": "4321",
     "levtype": "sfc",

tests/test_encoder_position_from_polytope.py

@@ -130,7 +130,7 @@ def test_reforecast_single_hdate_two_points(self):
 
         shared_metadata = {
             "class": "ce",
-            "date": np.datetime64("2024-03-01"),
+            "date": "2024-03-01",
             "Forecast date": "2025-07-14T06:00:00Z",
             "domain": "g",
             "expver": "4321",
@@ -168,7 +168,7 @@ def test_reforecast_two_hdates_two_points(self):
 
         shared_metadata = {
             "class": "ce",
-            "date": np.datetime64("2024-03-01"),
+            "date": "2024-03-01",
             "domain": "g",
             "expver": "4321",
             "levtype": "sfc",

tests/test_encoder_time_series_from_polytope.py

@@ -1,4 +1,8 @@
+import json
+
 import numpy as np
+import orjson
+import pytest
 from conftest import chain, make_leaf, make_point, node, tip
 from polytope_feature.datacube.tensor_index_tree import TensorIndexTree
 
@@ -29,7 +33,7 @@ def hdate_branch(hdate, lat, lon, result):
 
 EXPECTED_HDATE_METADATA = {
     "class": "ce",
-    "date": np.datetime64("2024-03-01"),
+    "date": "2024-03-01",
     "domain": "g",
     "expver": "4321",
     "levtype": "sfc",
@@ -199,12 +203,13 @@ def test_multiple_params(self):
 
 
 class TestTimeseriesFromPolytopeReforecast:
-    def test_single_point(self):
+    @pytest.mark.parametrize("date", [np.datetime64("2024-03-01"), np.datetime64("2024-03-01T00:00:00")])
+    def test_single_point(self, date):
         # 1 hdate (with time pre-merged by polytope-mars), 1 point
         tree = chain(
             TensorIndexTree(),
             node("class", ("ce",)),
-            node("date", (np.datetime64("2024-03-01"),)),
+            node("date", (date,)),
             hdate_branch(np.datetime64("2025-07-14T06:00:00"), 51.5, 6.5, [42.17]),
         )
 
@@ -231,7 +236,11 @@ def test_single_point(self):
             }
         }
 
-        assert cov["mars:metadata"] == {"Forecast date": "2025-07-14T06:00:00Z", **EXPECTED_HDATE_METADATA}
+        assert cov["mars:metadata"] == {
+            "Forecast date": "2025-07-14T06:00:00Z",
+            **EXPECTED_HDATE_METADATA,
+            "date": date.astype(str),
+        }
 
     def test_multiple_times(self):
         # 2 hdate values (pre-merged times from same day), 1 point → 2 coverages
@@ -453,3 +462,33 @@ def test_multiple_hdates_and_steps(self):
             assert cov["domain"]["axes"]["t"]["values"] == t
             assert cov["ranges"]["dis06"]["values"] == vals
             assert cov["mars:metadata"] == {"Forecast date": fc_date, **EXPECTED_HDATE_METADATA}
+
+    @pytest.mark.parametrize(
+        "json_module,date", [(json, np.datetime64("2024-03-01")), (orjson, np.datetime64("2024-03-01T00:00:00"))]
+    )
+    def test_reforecast_covjson_is_json_serialisable(self, json_module, date):
+        """CoverageJSON produced by from_polytope_reforecast must be serialisable
+        with both stdlib json and orjson (i.e. no numpy.datetime64 left in the
+        mars:metadata dict — regression test for the date axis leak)."""
+        tree = chain(
+            TensorIndexTree(),
+            node("class", ("ce",)),
+            node("date", (date,)),
+            hdate_branch(np.datetime64("2025-07-14T06:00:00"), 51.5, 6.5, [42.17]),
+        )
+
+        covjson = Covjsonkit().encode("CoverageCollection", "PointSeries").from_polytope_reforecast(tree)
+
+        # stdlib json.dumps must not raise TypeError
+        serialised = json_module.dumps(covjson)
+
+        # The 'date' value in mars:metadata must be a plain string, not numpy.datetime64
+        for cov in covjson["coverages"]:
+            date_val = cov["mars:metadata"].get("date")
+            assert not isinstance(
+                date_val, np.datetime64
+            ), f"mars:metadata['date'] is still a numpy.datetime64: {date_val!r}"
+
+        # Round-trip through the JSON module to ensure it can be deserialised back to a dict
+        deserialised = json_module.loads(serialised)
+        assert deserialised == covjson

tests/test_encoder_vertical_profile_from_polytope.py

@@ -200,7 +200,7 @@ class TestVerticalProfileFromPolytopeReforecast:
 
     EXPECTED_REFORECAST_METADATA = {
         "class": "ce",
-        "date": np.datetime64("2024-03-01"),
+        "date": "2024-03-01",
         "domain": "g",
         "expver": "4321",
         "levtype": "pl",