text: """Tests for input validation functions"""
  
  import warnings
  
  from tempfile import NamedTemporaryFile
  from itertools import product
  
  import numpy as np
  from numpy.testing import assert_array_equal
  import scipy.sparse as sp
  
  from sklearn.utils.testing import assert_true, assert_false, assert_equal
  from sklearn.utils.testing import assert_raises, assert_raises_regexp
  from sklearn.utils.testing import assert_no_warnings
  from sklearn.utils.testing import assert_warns_message
  from sklearn.utils.testing import assert_warns
  from sklearn.utils.testing import ignore_warnings
  from sklearn.utils.testing import SkipTest
  from sklearn.utils import as_float_array, check_array, check_symmetric
  from sklearn.utils import check_X_y
  from sklearn.utils.mocking import MockDataFrame
  from sklearn.utils.estimator_checks import NotAnArray
  from sklearn.random_projection import sparse_random_matrix
  from sklearn.linear_model import ARDRegression
  from sklearn.neighbors import KNeighborsClassifier
  from sklearn.ensemble import RandomForestRegressor
  from sklearn.svm import SVR
  from sklearn.datasets import make_blobs
  from sklearn.utils.validation import (
      has_fit_parameter,
      check_is_fitted,
      check_consistent_length,
  )
  
  from sklearn.exceptions import NotFittedError
  from sklearn.exceptions import DataConversionWarning
  
  from sklearn.utils.testing import assert_raise_message
  
  
  def test_as_float_array():
      # Test function for as_float_array
      X = np.ones((3, 10), dtype=np.int32)
      X = X + np.arange(10, dtype=np.int32)
      X2 = as_float_array(X, copy=False)
      assert_equal(X2.dtype, np.float32)
      # Another test
      X = X.astype(np.int64)
      X2 = as_float_array(X, copy=True)
      # Checking that the array wasn't overwritten
      assert_true(as_float_array(X, False) is not X)
      assert_equal(X2.dtype, np.float64)
      # Test int dtypes <= 32bit
      tested_dtypes = [np.bool,
                       np.int8, np.int16, np.int32,
                       np.uint8, np.uint16, np.uint32]
      for dtype in tested_dtypes:
          X = X.astype(dtype)
          X2 = as_float_array(X)
          assert_equal(X2.dtype, np.float32)
  
      # Test object dtype
      X = X.astype(object)
      X2 = as_float_array(X, copy=True)
      assert_equal(X2.dtype, np.float64)
  
      # Here, X is of the right type, it shouldn't be modified
      X = np.ones((3, 2), dtype=np.float32)
      assert_true(as_float_array(X, copy=False) is X)
      # Test that if X is fortran ordered it stays
      X = np.asfortranarray(X)
      assert_true(np.isfortran(as_float_array(X, copy=True)))
  
      # Test the copy parameter with some matrices
      matrices = [
          np.matrix(np.arange(5)),
          sp.csc_matrix(np.arange(5)).toarray(),
          sparse_random_matrix(10, 10, density=0.10).toarray()
      ]
      for M in matrices:
          N = as_float_array(M, copy=True)
          N[0, 0] = np.nan
          assert_false(np.isnan(M).any())
  
  
  def test_np_matrix():
      # Confirm that input validation code does not return np.matrix
      X = np.arange(12).reshape(3, 4)
  
      assert_false(isinstance(as_float_array(X), np.matrix))
      assert_false(isinstance(as_float_array(np.matrix(X)), np.matrix))
      assert_false(isinstance(as_float_array(sp.csc_matrix(X)), np.matrix))
  
  
  def test_memmap():
      # Confirm that input validation code doesn't copy memory mapped arrays
  
      asflt = lambda x: as_float_array(x, copy=False)
  
      with NamedTemporaryFile(prefix='sklearn-test') as tmp:
          M = np.memmap(tmp, shape=(10, 10), dtype=np.float32)
          M[:] = 0
  
          for f in (check_array, np.asarray, asflt):
              X = f(M)
              X[:] = 1
              assert_array_equal(X.ravel(), M.ravel())
              X[:] = 0
  
  
  def test_ordering():
      # Check that ordering is enforced correctly by validation utilities.
      # We need to check each validation utility, because a 'copy' without
      # 'order=K' will kill the ordering.
      X = np.ones((10, 5))
      for A in X, X.T:
          for copy in (True, False):
              B = check_array(A, order='C', copy=copy)
              assert_true(B.flags['C_CONTIGUOUS'])
              B = check_array(A, order='F', copy=copy)
              assert_true(B.flags['F_CONTIGUOUS'])
              if copy:
                  assert_false(A is B)
  
      X = sp.csr_matrix(X)
      X.data = X.data[::-1]
      assert_false(X.data.flags['C_CONTIGUOUS'])
  
  
  @ignore_warnings
  def test_check_array():
      # accept_sparse == None
      # raise error on sparse inputs
      X = [[1, 2], [3, 4]]
      X_csr = sp.csr_matrix(X)
      assert_raises(TypeError, check_array, X_csr)
      # ensure_2d
      X_array = check_array([0, 1, 2], ensure_2d=False)
      assert_equal(X_array.ndim, 1)
      # don't allow ndim > 3
      X_ndim = np.arange(8).reshape(2, 2, 2)
      assert_raises(ValueError, check_array, X_ndim)
      check_array(X_ndim, allow_nd=True)  # doesn't raise
      # force_all_finite
      X_inf = np.arange(4).reshape(2, 2).astype(np.float)
      X_inf[0, 0] = np.inf
      assert_raises(ValueError, check_array, X_inf)
      check_array(X_inf, force_all_finite=False)  # no raise
      # nan check
      X_nan = np.arange(4).reshape(2, 2).astype(np.float)
      X_nan[0, 0] = np.nan
      assert_raises(ValueError, check_array, X_nan)
      check_array(X_inf, force_all_finite=False)  # no raise
  
      # dtype and order enforcement.
      X_C = np.arange(4).reshape(2, 2).copy("C")
      X_F = X_C.copy("F")
      X_int = X_C.astype(np.int)
      X_float = X_C.astype(np.float)
      Xs = [X_C, X_F, X_int, X_float]
      dtypes = [np.int32, np.int, np.float, np.float32, None, np.bool, object]
      orders = ['C', 'F', None]
      copys = [True, False]
  
      for X, dtype, order, copy in product(Xs, dtypes, orders, copys):
          X_checked = check_array(X, dtype=dtype, order=order, copy=copy)
          if dtype is not None:
              assert_equal(X_checked.dtype, dtype)
          else:
              assert_equal(X_checked.dtype, X.dtype)
          if order == 'C':
              assert_true(X_checked.flags['C_CONTIGUOUS'])
              assert_false(X_checked.flags['F_CONTIGUOUS'])
          elif order == 'F':
              assert_true(X_checked.flags['F_CONTIGUOUS'])
              assert_false(X_checked.flags['C_CONTIGUOUS'])
          if copy:
              assert_false(X is X_checked)
          else:
              # doesn't copy if it was already good
              if (X.dtype == X_checked.dtype and
                      X_checked.flags['C_CONTIGUOUS'] == X.flags['C_CONTIGUOUS']
                      and X_checked.flags['F_CONTIGUOUS'] == X.flags['F_CONTIGUOUS']):
                  assert_true(X is X_checked)
  
      # allowed sparse != None
      X_csc = sp.csc_matrix(X_C)
      X_coo = X_csc.tocoo()
      X_dok = X_csc.todok()
      X_int = X_csc.astype(np.int)
      X_float = X_csc.astype(np.float)
  
      Xs = [X_csc, X_coo, X_dok, X_int, X_float]
      accept_sparses = [['csr', 'coo'], ['coo', 'dok']]
      for X, dtype, accept_sparse, copy in product(Xs, dtypes, accept_sparses,
                                                   copys):
          with warnings.catch_warnings(record=True) as w:
              X_checked = check_array(X, dtype=dtype,
                                      accept_sparse=accept_sparse, copy=copy)
          if (dtype is object or sp.isspmatrix_dok(X)) and len(w):
              message = str(w[0].message)
              messages = ["object dtype is not supported by sparse matrices",
                          "Can't check dok sparse matrix for nan or inf."]
              assert_true(message in messages)
          else:
              assert_equal(len(w), 0)
          if dtype is not None:
              assert_equal(X_checked.dtype, dtype)
          else:
              assert_equal(X_checked.dtype, X.dtype)
          if X.format in accept_sparse:
              # no change if allowed
              assert_equal(X.format, X_checked.format)
          else:
              # got converted
              assert_equal(X_checked.format, accept_sparse[0])
          if copy:
              assert_false(X is X_checked)
          else:
              # doesn't copy if it was already good
              if (X.dtype == X_checked.dtype and X.format == X_checked.format):
                  assert_true(X is X_checked)
  
      # other input formats
      # convert lists to arrays
      X_dense = check_array([[1, 2], [3, 4]])
      assert_true(isinstance(X_dense, np.ndarray))
      # raise on too deep lists
      assert_raises(ValueError, check_array, X_ndim.tolist())
      check_array(X_ndim.tolist(), allow_nd=True)  # doesn't raise
      # convert weird stuff to arrays
      X_no_array = NotAnArray(X_dense)
      result = check_array(X_no_array)
      assert_true(isinstance(result, np.ndarray))
  
  
  def test_check_array_pandas_dtype_object_conversion():
      # test that data-frame like objects with dtype object
      # get converted
      X = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype=np.object)
      X_df = MockDataFrame(X)
      assert_equal(check_array(X_df).dtype.kind, "f")
      assert_equal(check_array(X_df, ensure_2d=False).dtype.kind, "f")
      # smoke-test against dataframes with column named "dtype"
      X_df.dtype = "Hans"
      assert_equal(check_array(X_df, ensure_2d=False).dtype.kind, "f")
  
  
  def test_check_array_on_mock_dataframe():
      arr = np.array([[0.2, 0.7], [0.6, 0.5], [0.4, 0.1], [0.7, 0.2]])
      mock_df = MockDataFrame(arr)
      checked_arr = check_array(mock_df)
      assert_equal(checked_arr.dtype,
                   arr.dtype)
      checked_arr = check_array(mock_df, dtype=np.float32)
      assert_equal(checked_arr.dtype, np.dtype(np.float32))
  
  
  def test_check_array_dtype_stability():
      # test that lists with ints don't get converted to floats
      X = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
      assert_equal(check_array(X).dtype.kind, "i")
      assert_equal(check_array(X, ensure_2d=False).dtype.kind, "i")
  
  
  def test_check_array_dtype_warning():
      X_int_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
      X_float64 = np.asarray(X_int_list, dtype=np.float64)
      X_float32 = np.asarray(X_int_list, dtype=np.float32)
      X_int64 = np.asarray(X_int_list, dtype=np.int64)
      X_csr_float64 = sp.csr_matrix(X_float64)
      X_csr_float32 = sp.csr_matrix(X_float32)
      X_csc_float32 = sp.csc_matrix(X_float32)
      X_csc_int32 = sp.csc_matrix(X_int64, dtype=np.int32)
      y = [0, 0, 1]
      integer_data = [X_int64, X_csc_int32]
      float64_data = [X_float64, X_csr_float64]
      float32_data = [X_float32, X_csr_float32, X_csc_float32]
      for X in integer_data:
          X_checked = assert_no_warnings(check_array, X, dtype=np.float64,
                                         accept_sparse=True)
          assert_equal(X_checked.dtype, np.float64)
  
          X_checked = assert_warns(DataConversionWarning, check_array, X,
                                   dtype=np.float64,
                                   accept_sparse=True, warn_on_dtype=True)
          assert_equal(X_checked.dtype, np.float64)
  
          # Check that the warning message includes the name of the Estimator
          X_checked = assert_warns_message(DataConversionWarning,
                                           'SomeEstimator',
                                           check_array, X,
                                           dtype=[np.float64, np.float32],
                                           accept_sparse=True,
                                           warn_on_dtype=True,
                                           estimator='SomeEstimator')
          assert_equal(X_checked.dtype, np.float64)
  
          X_checked, y_checked = assert_warns_message(
              DataConversionWarning, 'KNeighborsClassifier',
              check_X_y, X, y, dtype=np.float64, accept_sparse=True,
              warn_on_dtype=True, estimator=KNeighborsClassifier())
  
          assert_equal(X_checked.dtype, np.float64)
  
      for X in float64_data:
          X_checked = assert_no_warnings(check_array, X, dtype=np.float64,
                                         accept_sparse=True, warn_on_dtype=True)
          assert_equal(X_checked.dtype, np.float64)
          X_checked = assert_no_warnings(check_array, X, dtype=np.float64,
                                         accept_sparse=True, warn_on_dtype=False)
          assert_equal(X_checked.dtype, np.float64)
  
      for X in float32_data:
          X_checked = assert_no_warnings(check_array, X,
                                         dtype=[np.float64, np.float32],
                                         accept_sparse=True)
          assert_equal(X_checked.dtype, np.float32)
          assert_true(X_checked is X)
  
          X_checked = assert_no_warnings(check_array, X,
                                         dtype=[np.float64, np.float32],
                                         accept_sparse=['csr', 'dok'],
                                         copy=True)
          assert_equal(X_checked.dtype, np.float32)
          assert_false(X_checked is X)
  
      X_checked = assert_no_warnings(check_array, X_csc_float32,
                                     dtype=[np.float64, np.float32],
                                     accept_sparse=['csr', 'dok'],
                                     copy=False)
      assert_equal(X_checked.dtype, np.float32)
      assert_false(X_checked is X_csc_float32)
      assert_equal(X_checked.format, 'csr')
  
  
  def test_check_array_accept_sparse_type_exception():
      X = [[1, 2], [3, 4]]
      X_csr = sp.csr_matrix(X)
      invalid_type = SVR()
  
      msg = ("A sparse matrix was passed, but dense data is required. "
             "Use X.toarray() to convert to a dense numpy array.")
      assert_raise_message(TypeError, msg,
                           check_array, X_csr, accept_sparse=False)
      assert_raise_message(TypeError, msg,
                           check_array, X_csr, accept_sparse=None)
  
      msg = ("Parameter 'accept_sparse' should be a string, "
             "boolean or list of strings. You provided 'accept_sparse={}'.")
      assert_raise_message(ValueError, msg.format(invalid_type),
                           check_array, X_csr, accept_sparse=invalid_type)
  
      msg = ("When providing 'accept_sparse' as a tuple or list, "
             "it must contain at least one string value.")
      assert_raise_message(ValueError, msg.format([]),
                           check_array, X_csr, accept_sparse=[])
      assert_raise_message(ValueError, msg.format(()),
                           check_array, X_csr, accept_sparse=())
  
      assert_raise_message(TypeError, "SVR",
                           check_array, X_csr, accept_sparse=[invalid_type])
  
      # Test deprecation of 'None'
      assert_warns(DeprecationWarning, check_array, X, accept_sparse=None)
  
  
  def test_check_array_accept_sparse_no_exception():
      X = [[1, 2], [3, 4]]
      X_csr = sp.csr_matrix(X)
  
      check_array(X_csr, accept_sparse=True)
      check_array(X_csr, accept_sparse='csr')
      check_array(X_csr, accept_sparse=['csr'])
      check_array(X_csr, accept_sparse=('csr',))
  
  
  def test_check_array_min_samples_and_features_messages():
      # empty list is considered 2D by default:
      msg = "0 feature(s) (shape=(1, 0)) while a minimum of 1 is required."
      assert_raise_message(ValueError, msg, check_array, [[]])
  
      # If considered a 1D collection when ensure_2d=False, then the minimum
      # number of samples will break:
      msg = "0 sample(s) (shape=(0,)) while a minimum of 1 is required."
      assert_raise_message(ValueError, msg, check_array, [], ensure_2d=False)
  
      # Invalid edge case when checking the default minimum sample of a scalar
      msg = "Singleton array array(42) cannot be considered a valid collection."
      assert_raise_message(TypeError, msg, check_array, 42, ensure_2d=False)
  
      # Simulate a model that would need at least 2 samples to be well defined
      X = np.ones((1, 10))
      y = np.ones(1)
      msg = "1 sample(s) (shape=(1, 10)) while a minimum of 2 is required."
      assert_raise_message(ValueError, msg, check_X_y, X, y,
                           ensure_min_samples=2)
  
      # The same message is raised if the data has 2 dimensions even if this is
      # not mandatory
      assert_raise_message(ValueError, msg, check_X_y, X, y,
                           ensure_min_samples=2, ensure_2d=False)
  
      # Simulate a model that would require at least 3 features (e.g. SelectKBest
      # with k=3)
      X = np.ones((10, 2))
      y = np.ones(2)
      msg = "2 feature(s) (shape=(10, 2)) while a minimum of 3 is required."
      assert_raise_message(ValueError, msg, check_X_y, X, y,
                           ensure_min_features=3)
  
      # Only the feature check is enabled whenever the number of dimensions is 2
      # even if allow_nd is enabled:
      assert_raise_message(ValueError, msg, check_X_y, X, y,
                           ensure_min_features=3, allow_nd=True)
  
      # Simulate a case where a pipeline stage as trimmed all the features of a
      # 2D dataset.
      X = np.empty(0).reshape(10, 0)
      y = np.ones(10)
      msg = "0 feature(s) (shape=(10, 0)) while a minimum of 1 is required."
      assert_raise_message(ValueError, msg, check_X_y, X, y)
  
      # nd-data is not checked for any minimum number of features by default:
      X = np.ones((10, 0, 28, 28))
      y = np.ones(10)
      X_checked, y_checked = check_X_y(X, y, allow_nd=True)
      assert_array_equal(X, X_checked)
      assert_array_equal(y, y_checked)
  
  
  def test_has_fit_parameter():
      assert_false(has_fit_parameter(KNeighborsClassifier, "sample_weight"))
      assert_true(has_fit_parameter(RandomForestRegressor, "sample_weight"))
      assert_true(has_fit_parameter(SVR, "sample_weight"))
      assert_true(has_fit_parameter(SVR(), "sample_weight"))
  
  
  def test_check_symmetric():
      arr_sym = np.array([[0, 1], [1, 2]])
      arr_bad = np.ones(2)
      arr_asym = np.array([[0, 2], [0, 2]])
  
      test_arrays = {'dense': arr_asym,
                     'dok': sp.dok_matrix(arr_asym),
                     'csr': sp.csr_matrix(arr_asym),
                     'csc': sp.csc_matrix(arr_asym),
                     'coo': sp.coo_matrix(arr_asym),
                     'lil': sp.lil_matrix(arr_asym),
                     'bsr': sp.bsr_matrix(arr_asym)}
  
      # check error for bad inputs
      assert_raises(ValueError, check_symmetric, arr_bad)
  
      # check that asymmetric arrays are properly symmetrized
      for arr_format, arr in test_arrays.items():
          # Check for warnings and errors
          assert_warns(UserWarning, check_symmetric, arr)
          assert_raises(ValueError, check_symmetric, arr, raise_exception=True)
  
          output = check_symmetric(arr, raise_warning=False)
          if sp.issparse(output):
              assert_equal(output.format, arr_format)
              assert_array_equal(output.toarray(), arr_sym)
          else:
              assert_array_equal(output, arr_sym)
  
  
  def test_check_is_fitted():
      # Check is ValueError raised when non estimator instance passed
      assert_raises(ValueError, check_is_fitted, ARDRegression, "coef_")
      assert_raises(TypeError, check_is_fitted, "SVR", "support_")
  
      ard = ARDRegression()
      svr = SVR()
  
      try:
          assert_raises(NotFittedError, check_is_fitted, ard, "coef_")
          assert_raises(NotFittedError, check_is_fitted, svr, "support_")
      except ValueError:
          assert False, "check_is_fitted failed with ValueError"
  
      # NotFittedError is a subclass of both ValueError and AttributeError
      try:
          check_is_fitted(ard, "coef_", "Random message %(name)s, %(name)s")
      except ValueError as e:
          assert_equal(str(e), "Random message ARDRegression, ARDRegression")
  
      try:
          check_is_fitted(svr, "support_", "Another message %(name)s, %(name)s")
      except AttributeError as e:
          assert_equal(str(e), "Another message SVR, SVR")
  
      ard.fit(*make_blobs())
      svr.fit(*make_blobs())
  
      assert_equal(None, check_is_fitted(ard, "coef_"))
      assert_equal(None, check_is_fitted(svr, "support_"))
  
  
  def test_check_consistent_length():
      check_consistent_length([1], [2], [3], [4], [5])
      check_consistent_length([[1, 2], [[1, 2]]], [1, 2], ['a', 'b'])
      check_consistent_length([1], (2,), np.array([3]), sp.csr_matrix((1, 2)))
      assert_raises_regexp(ValueError, 'inconsistent numbers of samples',
                           check_consistent_length, [1, 2], [1])
      assert_raises_regexp(TypeError, 'got <\w+ \'int\'>',
                           check_consistent_length, [1, 2], 1)
      assert_raises_regexp(TypeError, 'got <\w+ \'object\'>',
                           check_consistent_length, [1, 2], object())
  
      assert_raises(TypeError, check_consistent_length, [1, 2], np.array(1))
      # Despite ensembles having __len__ they must raise TypeError
      assert_raises_regexp(TypeError, 'estimator', check_consistent_length,
                           [1, 2], RandomForestRegressor())
      # XXX: We should have a test with a string, but what is correct behaviour?
  
  
  def test_check_dataframe_fit_attribute():
      # check pandas dataframe with 'fit' column does not raise error
      # https://github.com/scikit-learn/scikit-learn/issues/8415
      try:
          import pandas as pd
          X = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
          X_df = pd.DataFrame(X, columns=['a', 'b', 'fit'])
          check_consistent_length(X_df)
      except ImportError:
          raise SkipTest("Pandas not found")
  