code: def test_one_value(self):
      multiplexer = Multiplexer(int)
      output = multiplexer.run(value=[2])
      assert output == {"value": 2}
  
imports: import pytest
  from haystack.components.others import Multiplexer
label_desc: Use image node_id 1 for calling the TestMultiplexer obj's underlying member method code with example usage: obj.test_one_value() without return types