class_docstr: Tests for shared/alert_table.py
docstr: Alert Table - Delete Alert
docstr_tok: ["Alert","Table","-","Delete","Alert"]
code: def test_delete_alert(self):
      """Alert Table - Delete Alert"""
      self.alert_table.delete_alerts(
          [(alert.rule_name, alert.alert_id) for alert in self.alerts]
      )
      assert_equal(0, len(self.alert_table._table.scan()["Items"]))
  
imports: from datetime import datetime
  import os
  from botocore.exceptions import ClientError
  from mock import ANY, MagicMock, patch
  from moto import mock_dynamodb2
  from nose.tools import assert_equal, assert_raises
  from streamalert.shared import alert, alert_table
  from tests.unit.helpers.aws_mocks import setup_mock_alerts_table
label_desc: Use image node_id 14 for calling the TestAlertTable obj's underlying member method code with example usage: obj.test_delete_alert() without return types