code: def test_input_shape_fit():
      X = np.ones((15, 2))
      y = np.ones(20)
      ds_test = BaseDS()
      with pytest.raises(ValueError):
          ds_test.fit(X, y)
  
imports: import unittest.mock
  from unittest.mock import Mock, MagicMock
  import numpy
  import pytest
  from sklearn.exceptions import NotFittedError
  from sklearn.neighbors import KNeighborsClassifier
  from deslib.base import BaseDS
  from deslib.util.dfp import frienemy_pruning_preprocessed
  from .conftest import create_base_classifier
label_desc: Use image node_id 16 for calling a global function with example usage: test_input_shape_fit() without return types