test(avro): share the decoder list through a fixture

Add tests/avro/conftest.py with AVAILABLE_DECODERS and a decoder_class fixture, so tests run against every decoder without repeating the list.

The fixture avoids importing the constant across test modules: CI runs pytest on tests/avro/test_decoder.py on its own, where the repository root is not on sys.path and 'from tests.avro.conftest import ...' fails with ModuleNotFoundError.

Author: Rodrigo-Palma

tests/avro/conftest.py

@@ -0,0 +1,32 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from __future__ import annotations
+
+from collections.abc import Callable
+
+import pytest
+
+from pyiceberg.avro.decoder import BinaryDecoder, StreamingBinaryDecoder
+from pyiceberg.avro.decoder_fast import CythonBinaryDecoder
+
+AVAILABLE_DECODERS = [StreamingBinaryDecoder, CythonBinaryDecoder]
+
+
+@pytest.fixture(params=AVAILABLE_DECODERS)
+def decoder_class(request: pytest.FixtureRequest) -> Callable[[bytes], BinaryDecoder]:
+    """Run a test against every available decoder implementation."""
+    return request.param

tests/avro/test_resolver.py

@@ -21,8 +21,7 @@
 import pytest
 from pydantic import Field
 
-from pyiceberg.avro.decoder import BinaryDecoder, StreamingBinaryDecoder
-from pyiceberg.avro.decoder_fast import CythonBinaryDecoder
+from pyiceberg.avro.decoder import BinaryDecoder
 from pyiceberg.avro.file import AvroFile
 from pyiceberg.avro.reader import (
     DecimalReader,
@@ -423,7 +422,6 @@ def test_writer_missing_optional_in_read_schema() -> None:
     assert actual == expected
 
 
-@pytest.mark.parametrize("decoder_class", [StreamingBinaryDecoder, CythonBinaryDecoder])
 def test_enum_reader_skip_advances_the_decoder(decoder_class: Callable[[bytes], BinaryDecoder]) -> None:
     """Skipping an enum field must consume its bytes, or the next field is read from them."""
     # Two ints, zigzag encoded: the enum's ordinal 1, then the next field's value 12.
@@ -435,7 +433,6 @@ def test_enum_reader_skip_advances_the_decoder(decoder_class: Callable[[bytes],
     assert IntegerReader().read(decoder) == 12
 
 
-@pytest.mark.parametrize("decoder_class", [StreamingBinaryDecoder, CythonBinaryDecoder])
 def test_enum_reader_skip_matches_read(decoder_class: Callable[[bytes], BinaryDecoder]) -> None:
     """Reading and skipping must leave the decoder at the same position."""
     encoded = b"\x02\x18"