text: import pytest
  
  from trinity._utils.stddev import StandardDeviation
  
  
  @pytest.mark.parametrize(
      "data,expected",
      (
          ((4, 2, 5, 8, 6), 2.23606),
          ((1.5, 1.8, 7, 1.2, 1.35), 2.4863),
          ((2, 2, 2, 2, 2), 0),
          ((1, 3, 5, 7, 9), 3.1622),
          ((100, 200, 300, 400, 500, 1, 3, 5, 7, 9), 3.1622),
      ),
  )
  def test_standard_deviation(data, expected):
      stddev = StandardDeviation(window_size=5)
  
      for value in data:
          stddev.update(value)
  
      assert abs(stddev.value - expected) < 0.01
  