text: import pytest
  import extract_position_function as e4
  
  
  @pytest.fixture
  def average_input():
      return "|update| the positron location \
              particle accelerator is x:21.432"
  
  
  @pytest.fixture
  def null_input():
      """For whatever reason its null."""
      return None
  
  
  @pytest.fixture
  def error_input():
      """Something went wrong with the machine, so the log reports an error."""
      return "|error| calculation no work."
  
  def test_null_case(null_input):
      """Reads in a log that's None"""
      # NoneType Input
      assert e4.extract_position(null_input) == None
  
  def test_average_case(average_input):
      """Reads in a log from the device, and returns
      the location of the positron (if mentioned)."""
      # Expected Input - contains 'x:
      assert e4.extract_position(average_input) == "21.432"