Allow serializing and deserializing of named astropy units.

glue/core/state.py

@@ -65,6 +65,7 @@ def load(rec, context)
 import numpy as np
 from matplotlib.colors import Colormap
 from matplotlib import cm
+from astropy.units import NamedUnit, Unit
 from astropy.wcs import WCS
 import shapely
 
@@ -621,6 +622,16 @@ def _load_slice(rec, context):
     return slice(rec['start'], rec['stop'], rec['step'])
 
 
+@saver(NamedUnit)
+def _save_named_unit(unit, context):
+    return dict(named_unit=unit.to_string())
+
+
+@loader(NamedUnit)
+def _load_named_unit(rec, context):
+    return Unit(rec["named_unit"])
+
+
 @saver(WCS)
 def _save_wcs(wcs, context):
     return dict(header=wcs.to_header_string())

glue/core/tests/test_state.py

@@ -305,6 +305,14 @@ def test_datetime_component():
     assert isinstance(c2.data[0], np.datetime64)
 
 
+@requires_astropy
+def test_astropy_units():
+    import astropy.units as u
+    unit = u.m
+    unit2 = clone(unit)
+    assert unit2 is unit
+
+
 class DummyClass(object):
     pass