code: def test_time_learning_curve_splitter():
      result, logs = time_learning_curve_splitter(
          sample_data,
          "2015-05-05",
          time_column="time",
          holdout_gap=timedelta(days=31),
          min_samples=0,
      )
  
      assert len(result) == 4
      train_1 = sample_data.iloc[result[0][0]]
      test_1 = sample_data.iloc[result[0][1][0]]
      train_2 = sample_data.iloc[result[1][0]]
      train_3 = sample_data.iloc[result[2][0]]
      train_4 = sample_data.iloc[result[3][0]]
      test_4 = sample_data.iloc[result[3][1][0]]
  
      # the test sets must all be the same, and have no dates before 2015-05-05 + 31 days
      assert set(result[0][1][0]) == set(result[1][1][0])
      assert set(result[1][1][0]) == set(result[2][1][0])
      assert set(result[2][1][0]) == set(result[3][1][0])
      assert len(test_1[test_1.time <= "2015-06-05"]) == 0
  
      # every training set must contain the one before it, and have no dates after 2015-05-05
      assert set(result[0][0]).issubset(set(result[1][0]))
      assert set(result[1][0]).issubset(set(result[2][0]))
      assert set(result[2][0]).issubset(set(result[3][0]))
      assert len(train_4[train_4.time > "2015-05-05"]) == 0
  
      # the test set will contain all space
      assert set(test_4.space) == set(sample_data.space)
  
      # every training set must have dates after the previous one
      assert train_2.time.max() > train_1.time.max()
      assert train_3.time.max() > train_2.time.max()
  
file_path: fklearn/tests/validation/test_splitters.py
imports: from datetime import timedelta
  import pandas
  import pytest
  from fklearn.validation.splitters import k_fold_splitter, out_of_time_and_space_splitter, spatial_learning_curve_splitter, time_learning_curve_splitter, reverse_time_learning_curve_splitter, stability_curve_time_splitter, stability_curve_time_in_space_splitter, stability_curve_time_space_splitter, forward_stability_curve_time_splitter, time_and_space_learning_curve_splitter
label_desc: Use image node_id 5 for calling a global function with example usage: test_time_learning_curve_splitter() without return types