Don't import from tests (#1601)

* fix: move DummyStorageTransformer to zarr, and import it from tests instead of the other way around

* test: tests use relative imports instead of importing from zarr.test

* docs: release notes

* docs: add new section for unreleased v3 work

* docs: add heading to v3 release notes

Author: d-v-b

docs/release.rst

@@ -13,10 +13,22 @@ Release notes
     # to document your changes. On releases it will be
     # re-indented so that it does not show up in the notes.
 
+.. _unreleased(v3):
+
+Unreleased (v3)
+---------------
+
+Maintenance
+~~~~~~~~~~~
+
+* Remedy a situation where ``zarr-python`` was importing ``DummyStorageTransformer`` from the test suite. 
+  The dependency relationship is now reversed: the test suite imports this class from ``zarr-python``.
+  By :user:`Davis Bennett <d-v-b>` :issue:`1601`.
+
 .. _unreleased:
 
-Unreleased
-----------
+Unreleased (v2)
+---------------
 
 Docs
 ~~~~
@@ -61,7 +73,6 @@ Maintenance
 * Remove ``sphinx-rtd-theme`` dependency from ``pyproject.toml``.
   By :user:`Sanket Verma <MSanKeys963>` :issue:`1563`.
 
-
 .. _release_2.16.1:
 
 2.16.1

zarr/_storage/v3_storage_transformers.py

@@ -81,6 +81,22 @@ def create_empty(cls, store: "ShardingStorageTransformer"):
         )
 
 
+class DummyStorageTransfomer(StorageTransformer):
+    """For testing purposes. This class was previously defined in the test suite and imported
+    into Zarr, but now it has been moved here and the test suite will import it like any other part
+    of the Zarr library."""
+
+    TEST_CONSTANT = "test1234"
+
+    extension_uri = "https://purl.org/zarr/spec/storage_transformers/dummy/1.0"
+    valid_types = ["dummy_type"]
+
+    def __init__(self, _type, test_value) -> None:
+        super().__init__(_type)
+        assert test_value == self.TEST_CONSTANT
+        self.test_value = test_value
+
+
 class ShardingStorageTransformer(StorageTransformer):  # lgtm[py/missing-equals]
     """Implements sharding as a storage transformer, as described in the spec:
     https://zarr-specs.readthedocs.io/en/latest/extensions/storage-transformers/sharding/v1.0.html

zarr/meta.py

@@ -459,8 +459,10 @@ def _encode_storage_transformer_metadata(
 
     @classmethod
     def _decode_storage_transformer_metadata(cls, meta: Mapping) -> "StorageTransformer":
-        from zarr.tests.test_storage_v3 import DummyStorageTransfomer
-        from zarr._storage.v3_storage_transformers import ShardingStorageTransformer
+        from zarr._storage.v3_storage_transformers import (
+            ShardingStorageTransformer,
+            DummyStorageTransfomer,
+        )
 
         # This might be changed to a proper registry in the future
         KNOWN_STORAGE_TRANSFORMERS = [DummyStorageTransfomer, ShardingStorageTransformer]

zarr/tests/test_attrs.py

@@ -8,7 +8,7 @@
 from zarr.attrs import Attributes
 from zarr.storage import KVStore, DirectoryStore
 from zarr._storage.v3 import KVStoreV3
-from zarr.tests.util import CountingDict, CountingDictV3
+from .util import CountingDict, CountingDictV3
 from zarr.hierarchy import group
 
 

zarr/tests/test_convenience.py

@@ -43,7 +43,7 @@
     MemoryStoreV3,
     SQLiteStoreV3,
 )
-from zarr.tests.util import have_fsspec
+from .util import have_fsspec
 
 _VERSIONS = (2, 3) if v3_api_available else (2,)
 

zarr/tests/test_core.py

@@ -35,7 +35,11 @@
     BaseStore,
     v3_api_available,
 )
-from .._storage.v3_storage_transformers import ShardingStorageTransformer, v3_sharding_available
+from .._storage.v3_storage_transformers import (
+    DummyStorageTransfomer,
+    ShardingStorageTransformer,
+    v3_sharding_available,
+)
 from zarr.core import Array
 from zarr.errors import ArrayNotFoundError, ContainsGroupError
 from zarr.meta import json_loads
@@ -70,9 +74,9 @@
     SQLiteStoreV3,
     StoreV3,
 )
-from zarr.tests.test_storage_v3 import DummyStorageTransfomer
+
 from zarr.util import buffer_size
-from zarr.tests.util import abs_container, skip_test_env_var, have_fsspec, mktemp
+from .util import abs_container, skip_test_env_var, have_fsspec, mktemp
 
 # noinspection PyMethodMayBeStatic
 

zarr/tests/test_creation.py

@@ -8,6 +8,7 @@
 from numpy.testing import assert_array_equal
 
 from zarr._storage.store import DEFAULT_ZARR_VERSION
+from zarr._storage.v3_storage_transformers import DummyStorageTransfomer
 from zarr.codecs import Zlib
 from zarr.core import Array
 from zarr.creation import (
@@ -30,8 +31,7 @@
 from zarr._storage.store import v3_api_available
 from zarr._storage.v3 import DirectoryStoreV3, KVStoreV3
 from zarr.sync import ThreadSynchronizer
-from zarr.tests.test_storage_v3 import DummyStorageTransfomer
-from zarr.tests.util import mktemp, have_fsspec
+from .util import mktemp, have_fsspec
 
 
 _VERSIONS = (None, 2, 3) if v3_api_available else (None, 2)

zarr/tests/test_dim_separator.py

@@ -7,7 +7,7 @@
 import zarr
 from zarr.core import Array
 from zarr.storage import DirectoryStore, NestedDirectoryStore, FSStore
-from zarr.tests.util import have_fsspec
+from .util import have_fsspec
 
 
 needs_fsspec = pytest.mark.skipif(not have_fsspec, reason="needs fsspec")

zarr/tests/test_hierarchy.py

@@ -57,7 +57,7 @@
     LRUStoreCacheV3,
 )
 from zarr.util import InfoReporter, buffer_size
-from zarr.tests.util import skip_test_env_var, have_fsspec, abs_container, mktemp
+from .util import skip_test_env_var, have_fsspec, abs_container, mktemp
 
 
 _VERSIONS = (2, 3) if v3_api_available else (2,)

zarr/tests/test_indexing.py

@@ -13,7 +13,7 @@
     PartialChunkIterator,
 )
 
-from zarr.tests.util import CountingDict
+from .util import CountingDict
 
 
 def test_normalize_integer_selection():