docstr: AlertPublisher - AlertPublisherRepository - get_publisher() - SamplePublisher1
docstr_tok: ["AlertPublisher","-","AlertPublisherRepository","-","get_publisher","(",")","-","SamplePublisher1"]
code: def test_get_publisher():
      """AlertPublisher - AlertPublisherRepository - get_publisher() - SamplePublisher1"""
      publisher = AlertPublisherRepository.get_publisher(
          "tests.unit.streamalert.shared.test_publisher.SamplePublisher1"
      )
  
      assert_true(isinstance(publisher, SamplePublisher1))
  
imports: from mock import patch
  from nose.tools import assert_true, assert_equal, assert_false
  from streamalert.alert_processor.helpers import _assemble_alert_publisher_for_output
  from streamalert.shared.publisher import AlertPublisherRepository, AlertPublisher, CompositePublisher, DefaultPublisher, Register, WrappedFunctionPublisher
  from tests.unit.streamalert.alert_processor.helpers import get_alert
label_desc: Use image node_id 8 for calling the TestAlertPublisherRepository obj's underlying member method code with example usage: obj.test_get_publisher() without return types