class_docstr: Test shared EphemeralDriver
code: def setup(self):
      self._driver = construct_persistence_driver(
          {"driver": "ephemeral"}
      )
      self._driver.set("this", "that")
      self._driver.set("those", {"theys": "thens"})
  
imports: from nose.tools import assert_equal, assert_raises, assert_true
  from streamalert.shared.lookup_tables.drivers import EphemeralDriver, NullDriver
  from streamalert.shared.lookup_tables.drivers_factory import construct_persistence_driver
  from streamalert.shared.lookup_tables.errors import LookupTablesConfigurationError
label_desc: Use image node_id 2 for calling the TestEphemeralDriver obj's underlying member method code with example usage: obj.setup() without return types