per-codec tests for new codecs

Author: d-v-b

tests/test_codecs/conftest.py

@@ -0,0 +1,78 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any, ClassVar
+
+if TYPE_CHECKING:
+    from zarr.abc.codec import Codec
+    from zarr.core.common import CodecJSON_V2, CodecJSON_V3
+
+
+class BaseTestCodec:
+    """
+    A base class for testing codec classes.
+
+    Attributes
+    ----------
+
+    test_cls : type[Codec]
+        The codec class being tested
+    valid_json_v2 : ClassVar[tuple[CodecJSON_V2, ...]]
+        A tuple of valid JSON representations for Zarr format version 2.
+    valid_json_v2 : ClassVar[tuple[CodecJSON_V2, ...]]
+        A tuple of valid JSON representations for Zarr format version 2.
+    """
+
+    test_cls: type[Codec]
+    valid_json_v2: ClassVar[tuple[CodecJSON_V2, ...]]
+    valid_json_v3: ClassVar[tuple[CodecJSON_V3, ...]]
+
+    def test_from_json_roundtrip_v2(self, valid_json_v2: CodecJSON_V2) -> None:
+        codec = self.test_cls.from_json(valid_json_v2)
+        assert codec.to_json(zarr_format=2) == valid_json_v2
+
+    def test_from_json_roundtrip_v3(self, valid_json_v3: CodecJSON_V3) -> None:
+        codec = self.test_cls.from_json(valid_json_v3)
+        assert codec.to_json(zarr_format=3) == valid_json_v3
+
+
+def pytest_generate_tests(metafunc: Any) -> None:
+    """
+    This is a pytest hook to parametrize class-scoped fixtures.
+
+    This hook allows us to define class-scoped fixtures as class attributes and then
+    generate the parametrize calls for pytest. This allows the fixtures to be
+    reused across multiple tests within the same class.
+
+    For example, if you had a regular pytest class like this:
+
+    class TestClass:
+       @pytest.mark.parametrize("param_a", [1, 2, 3])
+        def test_method(self, param_a):
+            ...
+
+    Child classes inheriting from ``TestClass`` would not be able to override the ``param_a`` fixture
+
+    this implementation of ``pytest_generate_tests`` allows you to define class-scoped fixtures as
+    class attributes, which allows the following to work:
+
+    class TestExample:
+        param_a = [1, 2, 3]
+
+        def test_example(self, param_a):
+            ...
+
+    # this class will have its test_example method parametrized with the values of TestB.param_a
+    class TestB(TestExample):
+        param_a = [1, 2, 100, 10]
+
+    """
+    # Iterate over all the fixtures defined in the class
+    # and parametrize them with the values defined in the class
+    # This allows us to define class-scoped fixtures as class attributes
+    # and then generate the parametrize calls for pytest
+    for fixture_name in metafunc.fixturenames:
+        if hasattr(metafunc.cls, fixture_name):
+            params = getattr(metafunc.cls, fixture_name)
+            # Only parametrize if params is a tuple or list, not a function/method
+            if isinstance(params, (tuple, list)):
+                metafunc.parametrize(fixture_name, params, scope="class", ids=str)

tests/test_codecs/test_adler32.py

@@ -0,0 +1,11 @@
+import pytest
+
+from tests.test_codecs.conftest import BaseTestCodec
+from zarr.codecs import numcodecs as _numcodecs
+
+
+@pytest.mark.filterwarnings("ignore::zarr.errors.ZarrUserWarning")
+class TestAdler32Codec(BaseTestCodec):
+    test_cls = _numcodecs.Adler32
+    valid_json_v2 = ({"id": "adler32"},)
+    valid_json_v3 = ({"name": "adler32", "configuration": {}},)

tests/test_codecs/test_astype.py

@@ -0,0 +1,16 @@
+import pytest
+
+from tests.test_codecs.conftest import BaseTestCodec
+from zarr.codecs import numcodecs as _numcodecs
+
+
+@pytest.mark.filterwarnings("ignore::zarr.errors.ZarrUserWarning")
+class TestAsTypeCodec(BaseTestCodec):
+    test_cls = _numcodecs.AsType
+    valid_json_v2 = ({"id": "astype", "encode_dtype": "<f4", "decode_dtype": "<f4"},)
+    valid_json_v3 = (
+        {
+            "name": "astype",
+            "configuration": {"encode_dtype": "<f4", "decode_dtype": "<f4"},
+        },
+    )

tests/test_codecs/test_bitround.py

@@ -0,0 +1,16 @@
+import pytest
+
+from tests.test_codecs.conftest import BaseTestCodec
+from zarr.codecs import numcodecs as _numcodecs
+
+
+@pytest.mark.filterwarnings("ignore::zarr.errors.ZarrUserWarning")
+class TestBitRoundCodec(BaseTestCodec):
+    test_cls = _numcodecs.BitRound
+    valid_json_v2 = ({"id": "bitround", "keepbits": 8},)
+    valid_json_v3 = (
+        {
+            "name": "bitround",
+            "configuration": {"keepbits": 8},
+        },
+    )

tests/test_codecs/test_blosc.py

@@ -6,6 +6,7 @@
 from packaging.version import Version
 
 import zarr
+from tests.test_codecs.conftest import BaseTestCodec
 from zarr.abc.store import Store
 from zarr.codecs import BloscCodec
 from zarr.codecs.blosc import (
@@ -20,6 +21,31 @@
 from zarr.storage import StorePath
 
 
+class TestBloscCodec(BaseTestCodec):
+    test_cls = BloscCodec
+    valid_json_v2 = (
+        {
+            "id": "blosc",
+            "cname": "lz4",
+            "clevel": 5,
+            "shuffle": 1,
+            "blocksize": 0,
+        },
+    )
+    valid_json_v3 = (
+        {
+            "name": "blosc",
+            "configuration": {
+                "cname": "lz4",
+                "clevel": 5,
+                "shuffle": "shuffle",
+                "blocksize": 0,
+                "typesize": 1,
+            },
+        },
+    )
+
+
 @pytest.mark.parametrize("shuffle", BLOSC_SHUFFLE)
 @pytest.mark.parametrize("cname", BLOSC_CNAME)
 @pytest.mark.parametrize("clevel", [1, 2])

tests/test_codecs/test_blosc_numcodecs.py

@@ -0,0 +1,16 @@
+import pytest
+
+from tests.test_codecs.conftest import BaseTestCodec
+from zarr.codecs import numcodecs as _numcodecs
+
+
+@pytest.mark.filterwarnings("ignore::zarr.errors.ZarrUserWarning")
+class TestBloscNumcodecsCodec(BaseTestCodec):
+    test_cls = _numcodecs.Blosc
+    valid_json_v2 = ({"id": "blosc", "clevel": 5, "shuffle": 1, "blocksize": 0, "cname": "lz4"},)
+    valid_json_v3 = (
+        {
+            "name": "blosc",
+            "configuration": {"clevel": 5, "shuffle": 1, "blocksize": 0, "cname": "lz4"},
+        },
+    )

tests/test_codecs/test_bytes.py

@@ -4,6 +4,7 @@
 import pytest
 
 import zarr
+from tests.test_codecs.conftest import BaseTestCodec
 from zarr.abc.store import Store
 from zarr.codecs import BytesCodec
 from zarr.storage import StorePath
@@ -14,6 +15,24 @@
     from zarr.codecs.bytes import BytesJSON_V2, BytesJSON_V3
 
 
+class TestBytesCodec(BaseTestCodec):
+    test_cls = BytesCodec
+    valid_json_v2 = (
+        {
+            "id": "bytes",
+            "endian": "little",
+        },
+    )
+    valid_json_v3 = (
+        {
+            "name": "bytes",
+            "configuration": {
+                "endian": "little",
+            },
+        },
+    )
+
+
 @pytest.mark.parametrize("endian", ["big", "little"])
 def test_bytescodec_to_json(endian: Literal["big", "little"]) -> None:
     codec = BytesCodec(endian=endian)

tests/test_codecs/test_bz2.py

@@ -0,0 +1,16 @@
+import pytest
+
+from tests.test_codecs.conftest import BaseTestCodec
+from zarr.codecs import numcodecs as _numcodecs
+
+
+@pytest.mark.filterwarnings("ignore::zarr.errors.ZarrUserWarning")
+class TestBZ2Codec(BaseTestCodec):
+    test_cls = _numcodecs.BZ2
+    valid_json_v2 = ({"id": "bz2", "level": 1},)
+    valid_json_v3 = (
+        {
+            "name": "bz2",
+            "configuration": {"level": 1},
+        },
+    )

tests/test_codecs/test_crc32.py

@@ -0,0 +1,11 @@
+import pytest
+
+from tests.test_codecs.conftest import BaseTestCodec
+from zarr.codecs import numcodecs as _numcodecs
+
+
+@pytest.mark.filterwarnings("ignore::zarr.errors.ZarrUserWarning")
+class TestCRC32Codec(BaseTestCodec):
+    test_cls = _numcodecs.CRC32
+    valid_json_v2 = ({"id": "crc32"},)
+    valid_json_v3 = ({"name": "crc32", "configuration": {}},)

tests/test_codecs/test_crc32c.py

@@ -15,6 +15,7 @@
 from crc32c import crc32c
 
 import zarr
+from tests.test_codecs.conftest import BaseTestCodec
 from zarr.abc.store import Store
 from zarr.codecs.crc32c_ import (
     Crc32cCodec,
@@ -31,6 +32,12 @@
 from zarr.storage import StorePath
 
 
+class TestCrc32cCodec(BaseTestCodec):
+    test_cls = Crc32cCodec
+    valid_json_v2 = ({"id": "crc32c"},)
+    valid_json_v3 = ({"name": "crc32c"},)
+
+
 class TestCrc32cCodecJSON:
     """Test JSON serialization and deserialization for Crc32c codec."""