content: """
  Testing for the base module (sklearn.ensemble.base).
  """
  
  # Authors: Gilles Louppe
  # License: BSD 3 clause
  
  from numpy.testing import assert_equal
  from nose.tools import assert_true
  
  from sklearn.utils.testing import assert_raise_message
  from sklearn.datasets import load_iris
  from sklearn.ensemble import BaggingClassifier
  from sklearn.linear_model import Perceptron
  
  
  def test_base():
      # Check BaseEnsemble methods.
      ensemble = BaggingClassifier(base_estimator=Perceptron(), n_estimators=3)
  
      iris = load_iris()
      ensemble.fit(iris.data, iris.target)
      ensemble.estimators_ = []  # empty the list and create estimators manually
  
      ensemble._make_estimator()
      ensemble._make_estimator()
      ensemble._make_estimator()
      ensemble._make_estimator(append=False)
  
      assert_equal(3, len(ensemble))
      assert_equal(3, len(ensemble.estimators_))
  
      assert_true(isinstance(ensemble[0], Perceptron))
  
  
  def test_base_zero_n_estimators():
      # Check that instantiating a BaseEnsemble with n_estimators<=0 raises
      # a ValueError.
      ensemble = BaggingClassifier(base_estimator=Perceptron(), n_estimators=0)
      iris = load_iris()
      assert_raise_message(ValueError,
                           "n_estimators must be greater than zero, got 0.",
                           ensemble.fit, iris.data, iris.target)
  