Correct default fill_value for creation.create

Author: benjeffery

zarr/creation.py

@@ -16,7 +16,7 @@
 
 
 def create(shape, chunks=True, dtype=None, compressor='default',
-           fill_value=0, order='C', store=None, synchronizer=None,
+           fill_value=None, order='C', store=None, synchronizer=None,
            overwrite=False, path=None, chunk_store=None, filters=None,
            cache_metadata=True, cache_attrs=True, read_only=False,
            object_codec=None, dimension_separator=None,

zarr/tests/test_core.py

@@ -18,6 +18,7 @@
 from pkg_resources import parse_version
 
 from zarr.core import Array
+from zarr.creation import create
 from zarr.meta import json_loads
 from zarr.n5 import N5Store, N5FSStore, n5_keywords
 from zarr.storage import (
@@ -1249,6 +1250,14 @@ def test_object_arrays_vlen_bytes(self):
         assert_array_equal(data, z[:])
         z.store.close()
 
+        # Zero-length bytes
+        z = create(shape=(1,), dtype=bytes)
+        assert z.dtype == object
+        assert isinstance(z.filters[0], VLenBytes)
+        z[0] = b''
+        assert z[0] == b''
+        z.store.close()
+
         z = self.create_array(shape=data.shape, dtype=object, object_codec=Pickle())
         z[:] = data
         assert_array_equal(data, z[:])

zarr/tests/test_creation.py

@@ -433,7 +433,7 @@ def test_create():
     assert (100,) == z.chunks  # auto-chunks
     assert np.dtype(None) == z.dtype
     assert 'blosc' == z.compressor.codec_id
-    assert 0 == z.fill_value
+    assert None == z.fill_value
 
     # all specified
     z = create(100, chunks=10, dtype='i4', compressor=Zlib(1),

zarr/tests/test_storage.py

@@ -2207,7 +2207,7 @@ def test_read_write(self):
 
 
 def test_fill_value_change():
-    a = zarr.create((10, 10), dtype=int)
+    a = zarr.create((10, 10), dtype=int, fill_value=0)
 
     assert a[0, 0] == 0