code: def test_bin_mapper_n_features_transform():
      mapper = _BinMapper(n_bins=42, random_state=42).fit(DATA)
      err_msg = (
          "This estimator was fitted with 2 features but 4 got passed"
      )
      with pytest.raises(ValueError, match=err_msg):
          mapper.transform(np.repeat(DATA, 2, axis=1))
  
imports: import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_equal
  from sklearn.ensemble._hist_gradient_boosting.binning import _BinMapper, _find_binning_thresholds, _map_to_bins
  from sklearn.ensemble._hist_gradient_boosting.common import ALMOST_INF, X_BINNED_DTYPE, X_DTYPE
  from sklearn.utils._openmp_helpers import _openmp_effective_n_threads
label_desc: Use image node_id 6 for calling a global function with example usage: test_bin_mapper_n_features_transform() without return types