Merge pull request #146 from WilliamJamieson/feature/magunit

CHANGES.rst

@@ -3,6 +3,7 @@
 
 - Update pins for ``asdf``, ``asdf-coordinates-schemas``, ``numpy``, and ``packaging``. [#164]
 - Add serialization support for non-VOunits. [#142]
+- Add serialization support for ``MagUnit`` based units. [#146]
 
 0.3.0 (2022-11-29)
 ------------------

asdf_astropy/converters/__init__.py

@@ -11,6 +11,7 @@
     "EquivalencyConverter",
     "QuantityConverter",
     "UnitConverter",
+    "MagUnitConverter",
     "FitsConverter",
     "AsdfFitsConverter",
     "AstropyFitsConverter",
@@ -71,4 +72,4 @@
     TransformConverterBase,
     UnitsMappingConverter,
 )
-from .unit import EquivalencyConverter, QuantityConverter, UnitConverter
+from .unit import EquivalencyConverter, MagUnitConverter, QuantityConverter, UnitConverter

asdf_astropy/converters/unit/__init__.py

@@ -2,8 +2,10 @@
     "EquivalencyConverter",
     "QuantityConverter",
     "UnitConverter",
+    "MagUnitConverter",
 ]
 
 from .equivalency import EquivalencyConverter
+from .magunit import MagUnitConverter
 from .quantity import QuantityConverter
 from .unit import UnitConverter

asdf_astropy/converters/unit/magunit.py

@@ -0,0 +1,17 @@
+from asdf.extension import Converter
+
+
+class MagUnitConverter(Converter):
+    tags = ["tag:astropy.org:astropy/units/magunit-*"]
+
+    types = [
+        "astropy.units.function.logarithmic.MagUnit",
+    ]
+
+    def to_yaml_tree(self, obj, tag, ctx):
+        return {"unit": obj.physical_unit}
+
+    def from_yaml_tree(self, node, tag, ctx):
+        from astropy.units import mag
+
+        return mag(node["unit"])

asdf_astropy/converters/unit/tests/test_magunit.py

@@ -0,0 +1,53 @@
+import asdf
+import pytest
+from astropy import units
+
+
+def create_builtin_units():
+    return [u for u in list(units.__dict__.values()) if isinstance(u, units.MagUnit)]
+
+
+@pytest.mark.parametrize("unit", create_builtin_units())
+@pytest.mark.filterwarnings("ignore::astropy.units.core.UnitsWarning")
+def test_builtin_serialization(unit, tmp_path):
+    file_path = tmp_path / "test.asdf"
+    with asdf.AsdfFile() as af:
+        af["unit"] = unit
+        af.write_to(file_path)
+
+    with asdf.open(file_path) as af:
+        assert af["unit"].is_equivalent(unit)
+
+    with asdf.open(file_path, _force_raw_types=True) as af:
+        assert isinstance(af["unit"], asdf.tagged.TaggedDict)
+        assert af["unit"]._tag.startswith("tag:astropy.org:astropy/units/magunit-")
+
+
+def create_magunits():
+    magunits = []
+    for u in units.__dict__.values():
+        if isinstance(u, units.UnitBase) and not isinstance(u, units.MagUnit):
+            try:
+                magunit = units.mag(u)
+            except units.UnitConversionError:
+                pass
+            else:
+                magunits.append(magunit)
+
+    return magunits
+
+
+@pytest.mark.parametrize("unit", create_magunits())
+@pytest.mark.filterwarnings("ignore::astropy.units.core.UnitsWarning")
+def test_magunit_serialization(unit, tmp_path):
+    file_path = tmp_path / "test.asdf"
+    with asdf.AsdfFile() as af:
+        af["unit"] = unit
+        af.write_to(file_path)
+
+    with asdf.open(file_path) as af:
+        assert af["unit"].is_equivalent(unit)
+
+    with asdf.open(file_path, _force_raw_types=True) as af:
+        assert isinstance(af["unit"], asdf.tagged.TaggedDict)
+        assert af["unit"]._tag.startswith("tag:astropy.org:astropy/units/magunit-")

asdf_astropy/extensions.py

@@ -29,6 +29,7 @@
 from .converters.transform.spline import SplineConverter
 from .converters.transform.tabular import TabularConverter
 from .converters.unit.equivalency import EquivalencyConverter
+from .converters.unit.magunit import MagUnitConverter
 from .converters.unit.quantity import QuantityConverter
 from .converters.unit.unit import UnitConverter
 
@@ -512,6 +513,7 @@
 UNIT_CONVETERS = [
     UnitConverter(),
     EquivalencyConverter(),
+    MagUnitConverter(),
 ]
 
 

asdf_astropy/resources/manifests/units-1.0.0.yaml

@@ -17,3 +17,9 @@ tags:
     description: |-
       Supports serialization of equivalencies between units
       in certain contexts
+  - tag_uri: tag:astropy.org:astropy/units/magunit-1.0.0
+    schema_uri: http://astropy.org/schemas/astropy/units/magunit-1.0.0
+    title: Represents a Magnitude Unit
+    description: |-
+      Represents the serialization of the MagUnit units built into
+      astropy.

asdf_astropy/resources/schemas/units/magunit-1.0.0.yaml

@@ -0,0 +1,18 @@
+%YAML 1.1
+---
+$schema: "http://stsci.edu/schemas/yaml-schema/draft-01"
+id: "http://astropy.org/schemas/astropy/units/magunit-1.0.0"
+
+title: |
+  Represents a Magnitude Unit
+
+description: |
+  Represents the serialization of the MagUnit units built into
+  astropy.
+
+type: object
+properties:
+  unit:
+    oneOf:
+      - tag: "tag:stsci.edu:asdf/unit/unit-1.0.0"
+      - tag: "tag:astropy.org:astropy/units/unit-1.0.0"