code: def test_single_timeseries_sunny_day(self):
      train_set, test_set = train_test_split(
          constant_timeseries(value=123, length=10),
          test_size=2,
          input_size=1,
          horizon=2,
          vertical_split_type=MODEL_AWARE,
      )
  
      assert (
          len(train_set) == 7 and len(test_set) == 4
      ), "Wrong shapes: training set shape: {}; test set shape {}".format(
          len(train_set), len(test_set)
      )
  
imports: import pytest
  from darts.utils.model_selection import MODEL_AWARE, SIMPLE, train_test_split
  from darts.utils.timeseries_generation import constant_timeseries
label_desc: Use image node_id 18 for calling the TestClassTrainTestSplit obj's underlying member method code with example usage: obj.test_single_timeseries_sunny_day() without return types