add tests for deserializer

Author: sthulb

tests/unit/shared/test_dynamodb_deserializer.py

@@ -0,0 +1,51 @@
+from typing import Any, Dict, Optional
+
+import pytest
+
+from aws_lambda_powertools.shared.dynamodb_deserializer import TypeDeserializer
+
+
+class DeserialiserModel:
+    def __init__(self, data: dict):
+        self._data = data
+        self._deserializer = TypeDeserializer()
+
+    def _deserialize_dynamodb_dict(self) -> Optional[Dict[str, Any]]:
+        if self._data is None:
+            return None
+
+        return {k: self._deserializer.deserialize(v) for k, v in self._data.items()}
+
+    @property
+    def data(self) -> Optional[Dict[str, Any]]:
+        """The primary key attribute(s) for the DynamoDB item that was modified."""
+        return self._deserialize_dynamodb_dict()
+
+
+def test_deserializer():
+    model = DeserialiserModel(
+        {
+            "Id": {"S": "Id-123"},
+            "Name": {"S": "John Doe"},
+            "ZipCode": {"N": 12345},
+            "Things": {"L": [{"N": 0}, {"N": 1}, {"N": 2}, {"N": 3}]},
+            "MoreThings": {"M": {"a": {"S": "foo"}, "b": {"S": "bar"}}},
+        },
+    )
+
+    assert model.data.get("Id") == "Id-123"
+    assert model.data.get("Name") == "John Doe"
+    assert model.data.get("ZipCode") == 12345
+    assert model.data.get("Things") == [0, 1, 2, 3]
+    assert model.data.get("MoreThings") == {"a": "foo", "b": "bar"}
+
+
+def test_deserializer_error():
+    model = DeserialiserModel(
+        {
+            "Id": {"X": None},
+        },
+    )
+
+    with pytest.raises(TypeError):
+        model.data.get("Id")