code: def test_date_to_index():
      dr = date_range("20000101", periods=3000, freq="W")
      y = Series(np.arange(3000.0), index=dr)
      date_index = y.index
  
      index = date_to_index(date_index[0], date_index)
      assert_equal(index, 0)
      index = date_to_index(date_index[-1], date_index)
      assert_equal(index, date_index.shape[0] - 1)
  
      index = date_to_index("2009-08-02", date_index)
      assert_equal(index, 500)
      index = date_to_index("2009-08-04", date_index)
      assert_equal(index, 501)
      index = date_to_index("2009-08-01", date_index)
      assert_equal(index, 500)
      index = date_to_index(dt.datetime(2009, 8, 1), date_index)
      assert_equal(index, 500)
      with pytest.raises(ValueError):
          date_to_index(dt.date(2009, 8, 1), date_index)
      z = y + 0.0
      z.index = np.arange(3000)
      num_index = z.index
      with pytest.raises(ValueError):
          date_to_index(dt.datetime(2009, 8, 1), num_index)
      idx = date_range("1999-12-31", periods=3)
  
      df = DataFrame([1, 2, 3], index=idx[::-1])
      with pytest.raises(ValueError):
          date_to_index(idx[0], df.index)
  
      df = DataFrame([1, 2, 3], index=[idx[0]] * 3)
      with pytest.raises(ValueError):
          date_to_index(idx[0], df.index)
  
      with pytest.raises(ValueError):
          date_to_index("NaT", idx)
  
      #  check whether this also works for a localized datetimeindex
      date_index = date_range(
          "20000101", periods=3000, freq="W", tz="Europe/Berlin"
      )
      index = date_to_index(date_index[0], date_index)
      assert_equal(index, 0)
  
imports: from abc import abstractmethod
  import datetime
  import numpy
  from numpy.random import RandomState
  from numpy.testing import assert_equal
  from pandas import DataFrame, Series, Timedelta, date_range
  import pytest
  from arch import doc
  from arch.univariate.base import implicit_constant
  from arch.utility.array import ConcreteClassMeta, DocStringInheritor, cutoff_to_index, date_to_index, ensure1d, ensure2d, find_index, parse_dataframe
label_desc: Use image node_id 7 for calling a global function with example usage: test_date_to_index() without return types