code: def test_fit(create_X_y, create_pool_classifiers):
      X, y = create_X_y
      a_posteriori_test = APosteriori(create_pool_classifiers)
      a_posteriori_test.fit(X, y)
      expected = np.array([[0.5, 0.5], [1.0, 0.0], [0.33, 0.67]])
      expected = np.tile(expected, (15, 1, 1))
      assert np.array_equal(a_posteriori_test.dsel_scores_, expected)
  
file_path: DESlib/deslib/tests/dcs/test_a_posteriori.py
imports: from unittest.mock import MagicMock
  import numpy
  import pytest
  from sklearn.linear_model import Perceptron
  from sklearn.utils.estimator_checks import check_estimator
  from deslib.dcs.a_posteriori import APosteriori
label_desc: Use image node_id 6 for calling a global function with example usage: test_fit(create_X_y, create_pool_classifiers) without return types