alternator-test: migrate filled_test_table to use batches

Filled test table fixture now takes advantage of batch writes
in order to run faster.
Message-Id: <e299cdffa9131d36465481ca3246199502d65e0c.1557914382.git.sarna@scylladb.com>

alternator-test/conftest.py

@@ -135,9 +135,9 @@ def filled_test_table(dynamodb):
         'another': "y" * 16
     } for i in range(count)]
 
-    for item in items:
-        # TODO: eventually, when Alternator supports batch operations,
-        # use a batch write to make this fixture start faster.
-        table.put_item(Item=item)
+    with table.batch_writer() as batch:
+        for item in items:
+            batch.put_item(item)
+
     yield table, items
     table.delete()

alternator-test/test_item.py

@@ -47,7 +47,6 @@ def test_basic_batch_write_item(dynamodb, test_table):
 
     for i in range(count):
         item = test_table.get_item(Key={'p': "batch{}".format(i), 'c': "batch_ck{}".format(i)}, ConsistentRead=True)['Item']
-        print(item)
         assert item['p'] == "batch{}".format(i)
         assert item['c'] == "batch_ck{}".format(i)
         assert item['attribute'] == str(i)