Add CSV serialization

src/py_adapter/plugin/__init__.py

@@ -53,10 +53,11 @@ def manager() -> pluggy.PluginManager:
 
 def _load_default_plugins(manager_: pluggy.PluginManager) -> None:
     """Load plugins that are packaged with py-adapter"""
-    from py_adapter.plugin import _avro, _json
+    from py_adapter.plugin import _avro, _csv, _json
 
     default_plugins = {
         "Avro": _avro,
+        "CSV": _csv,
         "JSON": _json,
     }
     for name, plugin in default_plugins.items():

src/py_adapter/plugin/_csv.py

@@ -0,0 +1,41 @@
+# Copyright 2023 J.P. Morgan Chase & Co.
+#
+# Licensed 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.
+
+"""
+CSV serializer/deserializer **py-adapter** plugin
+"""
+
+import io
+from typing import BinaryIO
+
+import py_adapter
+
+
+@py_adapter.plugin.hook
+def serialize(obj: py_adapter.Basic, stream: BinaryIO) -> BinaryIO:
+    """
+    Serialize an object of basic Python types as CSV data
+
+    :param obj:    Python object to serialize
+    :param stream: File-like object to serialize data to
+    """
+    import csv
+
+    text_stream = io.StringIO(newline="")  # csv modules writes as text
+    csv_writer = csv.DictWriter(text_stream, fieldnames=obj.keys())
+    csv_writer.writeheader()
+    csv_writer.writerow(obj)
+    text_stream.flush()
+    text_stream.seek(0)
+
+    stream.write(text_stream.read().encode("utf-8"))
+    stream.flush()
+    return stream

tests/test_csv.py

@@ -0,0 +1,42 @@
+# Copyright 2023 J.P. Morgan Chase & Co.
+#
+# Licensed 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.
+
+"""
+Test script for CSV serialization/deserialization
+"""
+
+import dataclasses
+import datetime
+from typing import Optional
+
+import pytest
+
+import py_adapter
+
+
+@dataclasses.dataclass
+class SimpleShip:
+    name: str
+    build_on: Optional[datetime.date] = None
+
+
+@pytest.fixture
+def simple_ship():
+    return SimpleShip(
+        name="Elvira",
+        build_on=datetime.date(1970, 12, 31),
+    )
+
+
+def test_serialize_1_record(simple_ship):
+    data = py_adapter.serialize(simple_ship, format="CSV")
+    expected_lines = [b"name,build_on", b"Elvira,1970-12-31"]
+    assert data.splitlines() == expected_lines

tests/test_serialize.py

@@ -25,7 +25,7 @@ def test_invalid_format(ship_obj):
         py_adapter.plugin.InvalidFormat,
         match=re.escape(
             "A plugin for serialization format 'does not exist' is not available. Installed plugins/formats are: "
-            "['Avro', 'JSON']."
+            "['Avro', 'CSV', 'JSON']."
         ),
     ):
         py_adapter.serialize(ship_obj, format="does not exist")