class_docstr: Test shared Alert class.
docstr: Alert Class - To String
docstr_tok: ["Alert","Class","-","To","String"]
code: def test_str(self):
      """Alert Class - To String"""
      alert = self._customized_alert()
      assert_equal(
          "<Alert abc-123 triggered from test_rule>", str(alert)
      )
  
imports: import copy
  from datetime import datetime, timedelta
  import json
  from nose.tools import assert_equal, assert_false, assert_is_instance, assert_not_in, assert_raises, assert_true
  from streamalert.shared.alert import Alert, AlertCreationError
label_desc: Use image node_id 7 for calling the TestAlert obj's underlying member method code with example usage: obj.test_str() without return types