Allow single values for JSON (#366)

Co-authored-by: jakirkham <[email protected]>

Author: martindurant

numcodecs/json.py

@@ -58,14 +58,18 @@ def encode(self, buf):
             buf = np.asarray(buf)
         except ValueError:
             buf = np.asarray(buf, dtype=object)
-        items = buf.tolist()
-        items.extend((buf.dtype.str, buf.shape))
+        items = np.atleast_1d(buf).tolist()
+        items.append(buf.dtype.str)
+        items.append(buf.shape)
         return self._encoder.encode(items).encode(self._text_encoding)
 
     def decode(self, buf, out=None):
         items = self._decoder.decode(ensure_text(buf, self._text_encoding))
         dec = np.empty(items[-1], dtype=items[-2])
-        dec[:] = items[:-2]
+        if not items[-1]:
+            dec[...] = items[0]
+        else:
+            dec[:] = items[:-2]
         if out is not None:
             np.copyto(out, dec)
             return out

numcodecs/tests/test_json.py

@@ -1,6 +1,5 @@
 import itertools
 
-
 import numpy as np
 import pytest
 
@@ -65,11 +64,16 @@ def test_backwards_compatibility():
         (["11", "1", "1"],  None),
         ([{}], None),
         ([{"key": "value"}, ["list", "of", "strings"]], object),
+        ([0], None),
+        ([{'hi': 0}], "object"),
+        (["hi"], "object"),
+        (0, None)
     ]
 )
 def test_non_numpy_inputs(input_data, dtype):
     # numpy will infer a range of different shapes and dtypes for these inputs.
     # Make sure that round-tripping through encode preserves this.
+    data = np.array(input_data, dtype=dtype)
     for codec in codecs:
-        output_data = codec.decode(codec.encode(input_data))
-        assert np.array_equal(np.array(input_data, dtype=dtype), output_data)
+        output_data = codec.decode(codec.encode(data))
+        assert input_data == output_data.tolist()