content: import numpy as np
  from pandas import Series
  from pandas import date_range
  from statsmodels.tsa.base.tsa_model import TimeSeriesModel
  import numpy.testing as npt
  from statsmodels.tools.testing import assert_equal
  
  def test_pandas_nodates_index():
      from statsmodels.datasets import sunspots
      y = sunspots.load_pandas().data.SUNACTIVITY
      npt.assert_raises(ValueError, TimeSeriesModel, y)
  
  def test_predict_freq():
      # test that predicted dates have same frequency
      x = np.arange(1,36.)
  
      # there's a bug in pandas up to 0.10.2 for YearBegin
      #dates = date_range("1972-4-1", "2007-4-1", freq="AS-APR")
      dates = date_range("1972-4-30", "2006-4-30", freq="A-APR")
      series = Series(x, index=dates)
      model = TimeSeriesModel(series)
      #npt.assert_(model.data.freq == "AS-APR")
      npt.assert_(model.data.freq == "A-APR")
  
      start = model._get_predict_start("2006-4-30")
      end = model._get_predict_end("2016-4-30")
      model._make_predict_dates()
  
      predict_dates = model.data.predict_dates
  
      #expected_dates = date_range("2006-12-31", "2016-12-31",
      #                            freq="AS-APR")
      expected_dates = date_range("2006-4-30", "2016-4-30", freq="A-APR")
      assert_equal(predict_dates, expected_dates)
      #ptesting.assert_series_equal(predict_dates, expected_dates)
  
  
  def test_keyerror_start_date():
      x = np.arange(1,36.)
  
      from pandas import date_range
  
      # there's a bug in pandas up to 0.10.2 for YearBegin
      #dates = date_range("1972-4-1", "2007-4-1", freq="AS-APR")
      dates = date_range("1972-4-30", "2006-4-30", freq="A-APR")
      series = Series(x, index=dates)
      model = TimeSeriesModel(series)
  
      npt.assert_raises(ValueError, model._get_predict_start, "1970-4-30")
  
  def test_period_index():
      # test 1285
      from pandas import PeriodIndex, TimeSeries
      dates = PeriodIndex(start="1/1/1990", periods=20, freq="M")
      x = np.arange(1, 21.)
  
      model = TimeSeriesModel(Series(x, index=dates))
      npt.assert_(model.data.freq == "M")
      model = TimeSeriesModel(TimeSeries(x, index=dates))
      npt.assert_(model.data.freq == "M")
  