code: def test_forecasting_residuals_nocov_output(self):
      model = NaiveSeasonal(K=1)
  
      # test zero residuals
      constant_ts = ct(length=20)
      residuals = model.residuals(constant_ts)
      np.testing.assert_almost_equal(
          residuals.univariate_values(), np.zeros(len(residuals))
      )
  
      # test constant, positive residuals
      linear_ts = lt(length=20)
      residuals = model.residuals(linear_ts)
      np.testing.assert_almost_equal(
          np.diff(residuals.univariate_values()),
          np.zeros(len(residuals) - 1),
      )
      np.testing.assert_array_less(
          np.zeros(len(residuals)), residuals.univariate_values()
      )
  
file_path: darts/darts/tests/utils/test_residuals.py
imports: import numpy
  import pytest
  from darts.logging import get_logger
  from darts.models import LinearRegressionModel, NaiveSeasonal
  from darts.tests.models.forecasting.test_regression_models import dummy_timeseries
  from darts.utils.timeseries_generation import constant_timeseries
  from darts.utils.timeseries_generation import linear_timeseries
label_desc: Use image node_id 1 for calling the TestResiduals obj's underlying member method code with example usage: obj.test_forecasting_residuals_nocov_output() without return types