test: add comprehensive tests for S3 IntelligentTiering events

Relates to #7443

Add test event and comprehensive test coverage for both parser models
and data classes handling of S3 IntelligentTiering events.

Changes:
- Add s3EventIntelligentTiering.json test event
- Add parser model tests (2 tests)
- Add data classes tests (3 tests)
- Tests verify get_object field handling and intelligentTieringEventData

Author: oyiz-michael

tests/events/s3EventIntelligentTiering.json

@@ -0,0 +1,42 @@
+{
+  "Records": [
+    {
+      "eventVersion": "2.3",
+      "eventSource": "aws:s3",
+      "awsRegion": "ap-southeast-2",
+      "eventTime": "2025-09-29T00:47:23.967Z",
+      "eventName": "IntelligentTiering",
+      "userIdentity": {
+        "principalId": "s3.amazonaws.com"
+      },
+      "requestParameters": {
+        "sourceIPAddress": "s3.amazonaws.com"
+      },
+      "responseElements": {
+        "x-amz-request-id": "4C05BE601E268FCD",
+        "x-amz-id-2": "Wt0dgzBP/wQ47PWP5BqoD4nAZC08NOjfdZj2prx5gVPBCI+YQtrx/UKVlnT63Dj+vse4x5koWp61HaoVyz6fUFe1yLkhNpK3"
+      },
+      "s3": {
+        "s3SchemaVersion": "1.0",
+        "configurationId": "ZDM3MGVjY2MtZTlmNC00ZTk0LThiNjItMWJiNTMwOTYwY2Rl",
+        "bucket": {
+          "name": "mybucket",
+          "ownerIdentity": {
+            "principalId": "ANY597T3BWFY2"
+          },
+          "arn": "arn:aws:s3:::mybucket"
+        },
+        "get_object": {
+          "key": "myobject",
+          "size": 252294,
+          "eTag": "4e9270240d7d62d5ee8dbfcb7a7a3279",
+          "versionId": "tiogA9Ga7Xi49yfJ6lkeTxPYx7ZK75yn",
+          "sequencer": "0066A8D0E77DE42BC5"
+        }
+      },
+      "intelligentTieringEventData": {
+        "destinationAccessTier": "ARCHIVE_ACCESS"
+      }
+    }
+  ]
+}

tests/unit/data_classes/required_dependencies/test_s3_intelligent_tiering_event.py

@@ -0,0 +1,64 @@
+from aws_lambda_powertools.utilities.data_classes import S3Event
+from tests.functional.utils import load_event
+
+
+def test_s3_intelligent_tiering_event():
+    """Test S3 IntelligentTiering event with get_object field"""
+    event = S3Event(load_event("s3EventIntelligentTiering.json"))
+
+    # Test first record
+    record = event.record
+    assert record.event_name == "IntelligentTiering"
+    assert record.event_version == "2.3"
+    assert record.event_source == "aws:s3"
+    assert record.aws_region == "ap-southeast-2"
+
+    # Test user identity
+    assert record.user_identity.principal_id == "s3.amazonaws.com"
+
+    # Test S3 object via get_object property (handles both 'object' and 'get_object' keys)
+    s3_object = record.s3.get_object
+    assert s3_object.key == "myobject"
+    assert s3_object.size == 252294
+    assert s3_object.etag == "4e9270240d7d62d5ee8dbfcb7a7a3279"
+    assert s3_object.version_id == "tiogA9Ga7Xi49yfJ6lkeTxPYx7ZK75yn"
+    assert s3_object.sequencer == "0066A8D0E77DE42BC5"
+
+    # Test bucket
+    assert record.s3.bucket.name == "mybucket"
+    assert record.s3.bucket.arn == "arn:aws:s3:::mybucket"
+
+    # Test intelligentTieringEventData
+    assert record.intelligent_tiering_event_data is not None
+    assert record.intelligent_tiering_event_data.destination_access_tier == "ARCHIVE_ACCESS"
+
+    # Verify glacierEventData is None
+    assert record.glacier_event_data is None
+
+    # Test convenience properties
+    assert event.bucket_name == "mybucket"
+    assert event.object_key == "myobject"
+
+
+def test_s3_intelligent_tiering_event_iteration():
+    """Test iterating through multiple IntelligentTiering records"""
+    event = S3Event(load_event("s3EventIntelligentTiering.json"))
+
+    records = list(event.records)
+    assert len(records) == 1
+
+    for record in event.records:
+        assert record.event_name == "IntelligentTiering"
+        assert record.s3.get_object.key == "myobject"
+        assert record.intelligent_tiering_event_data.destination_access_tier == "ARCHIVE_ACCESS"
+
+
+def test_s3_intelligent_tiering_deep_archive_access():
+    """Test IntelligentTiering event with DEEP_ARCHIVE_ACCESS tier"""
+    raw_event = load_event("s3EventIntelligentTiering.json")
+    raw_event["Records"][0]["intelligentTieringEventData"]["destinationAccessTier"] = "DEEP_ARCHIVE_ACCESS"
+
+    event = S3Event(raw_event)
+    record = event.record
+
+    assert record.intelligent_tiering_event_data.destination_access_tier == "DEEP_ARCHIVE_ACCESS"

tests/unit/parser/_pydantic/test_s3_intelligent_tiering.py

@@ -0,0 +1,76 @@
+from aws_lambda_powertools.utilities.parser.models import S3Model, S3RecordModel
+from tests.functional.utils import load_event
+
+
+def test_s3_intelligent_tiering_event():
+    """Test parsing of S3 IntelligentTiering events with get_object field"""
+    raw_event = load_event("s3EventIntelligentTiering.json")
+    parsed_event: S3Model = S3Model(**raw_event)
+
+    records = list(parsed_event.Records)
+    assert len(records) == 1
+
+    record: S3RecordModel = records[0]
+    raw_record = raw_event["Records"][0]
+
+    # Verify basic event properties
+    assert record.eventVersion == "2.3"
+    assert record.eventSource == "aws:s3"
+    assert record.awsRegion == "ap-southeast-2"
+    assert record.eventName == "IntelligentTiering"
+
+    # Verify user identity
+    user_identity = record.userIdentity
+    assert user_identity.principalId == "s3.amazonaws.com"
+
+    # Verify request parameters
+    request_parameters = record.requestParameters
+    # Note: sourceIPAddress is "s3.amazonaws.com" for IntelligentTiering events, not an IP
+    assert str(request_parameters.sourceIPAddress) == "s3.amazonaws.com"
+
+    # Verify response elements
+    assert record.responseElements.x_amz_request_id == raw_record["responseElements"]["x-amz-request-id"]
+    assert record.responseElements.x_amz_id_2 == raw_record["responseElements"]["x-amz-id-2"]
+
+    # Verify S3 message
+    s3 = record.s3
+    assert s3.s3SchemaVersion == raw_record["s3"]["s3SchemaVersion"]
+    assert s3.configurationId == raw_record["s3"]["configurationId"]
+
+    # Verify bucket
+    bucket = s3.bucket
+    raw_bucket = raw_record["s3"]["bucket"]
+    assert bucket.name == "mybucket"
+    assert bucket.ownerIdentity.principalId == raw_bucket["ownerIdentity"]["principalId"]
+    assert bucket.arn == "arn:aws:s3:::mybucket"
+
+    # Verify get_object field (IntelligentTiering uses 'get_object' instead of 'object')
+    assert s3.get_object is not None
+    assert s3.get_object.key == "myobject"
+    assert s3.get_object.size == 252294
+    assert s3.get_object.eTag == "4e9270240d7d62d5ee8dbfcb7a7a3279"
+    assert s3.get_object.versionId == "tiogA9Ga7Xi49yfJ6lkeTxPYx7ZK75yn"
+    assert s3.get_object.sequencer == "0066A8D0E77DE42BC5"
+
+    # Verify intelligentTieringEventData
+    assert record.intelligentTieringEventData is not None
+    assert record.intelligentTieringEventData.destinationAccessTier == "ARCHIVE_ACCESS"
+
+    # Verify glacierEventData is None for IntelligentTiering events
+    assert record.glacierEventData is None
+
+
+def test_s3_intelligent_tiering_event_access_tiers():
+    """Test different access tier values for IntelligentTiering events"""
+    raw_event = load_event("s3EventIntelligentTiering.json")
+
+    # Test ARCHIVE_ACCESS tier (from the test event)
+    parsed_event: S3Model = S3Model(**raw_event)
+    record = list(parsed_event.Records)[0]
+    assert record.intelligentTieringEventData.destinationAccessTier == "ARCHIVE_ACCESS"
+
+    # Test DEEP_ARCHIVE_ACCESS tier
+    raw_event["Records"][0]["intelligentTieringEventData"]["destinationAccessTier"] = "DEEP_ARCHIVE_ACCESS"
+    parsed_event: S3Model = S3Model(**raw_event)
+    record = list(parsed_event.Records)[0]
+    assert record.intelligentTieringEventData.destinationAccessTier == "DEEP_ARCHIVE_ACCESS"