Merge pull request #2329 from swen128/bugfix/dynamodb/update-item

Fix DynamoDB update_item to deal with list-type attributes

moto/dynamodb2/models.py

@@ -298,7 +298,9 @@ class Item(BaseModel):
             new_value = list(update_action['Value'].values())[0]
             if action == 'PUT':
                 # TODO deal with other types
-                if isinstance(new_value, list) or isinstance(new_value, set):
+                if isinstance(new_value, list):
+                    self.attrs[attribute_name] = DynamoType({"L": new_value})
+                elif isinstance(new_value, set):
                     self.attrs[attribute_name] = DynamoType({"SS": new_value})
                 elif isinstance(new_value, dict):
                     self.attrs[attribute_name] = DynamoType({"M": new_value})

tests/test_dynamodb2/test_dynamodb.py

@@ -1342,6 +1342,46 @@ def test_query_missing_expr_names():
     resp['Items'][0]['client']['S'].should.equal('test2')
 
 
+# https://github.com/spulec/moto/issues/2328
+@mock_dynamodb2
+def test_update_item_with_list():
+    dynamodb = boto3.resource('dynamodb', region_name='us-east-1')
+
+    # Create the DynamoDB table.
+    dynamodb.create_table(
+        TableName='Table',
+        KeySchema=[
+            {
+                'AttributeName': 'key',
+                'KeyType': 'HASH'
+            }
+        ],
+        AttributeDefinitions=[
+            {
+                'AttributeName': 'key',
+                'AttributeType': 'S'
+            },
+        ],
+        ProvisionedThroughput={
+            'ReadCapacityUnits': 1,
+            'WriteCapacityUnits': 1
+        }
+    )
+    table = dynamodb.Table('Table')
+    table.update_item(
+        Key={'key': 'the-key'},
+        AttributeUpdates={
+            'list': {'Value': [1, 2], 'Action': 'PUT'}
+        }
+    )
+
+    resp = table.get_item(Key={'key': 'the-key'})
+    resp['Item'].should.equal({
+        'key': 'the-key',
+        'list': [1, 2]
+    })
+
+
 # https://github.com/spulec/moto/issues/1342
 @mock_dynamodb2
 def test_update_item_on_map():