code: def test_bin_mapper_idempotence(max_bins_small, max_bins_large):
      assert max_bins_large >= max_bins_small
      data = np.random.RandomState(42).normal(size=30000).reshape(-1, 1)
      mapper_small = _BinMapper(n_bins=max_bins_small + 1)
      mapper_large = _BinMapper(n_bins=max_bins_small + 1)
      binned_small = mapper_small.fit_transform(data)
      binned_large = mapper_large.fit_transform(binned_small)
      assert_array_equal(binned_small, binned_large)
  
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 13 for calling a global function with example usage: test_bin_mapper_idempotence(max_bins_small, max_bins_large) without return types