code: def test_invalid_lookback(self):
      data = arange(30, dtype=float).reshape(6, 5)
      adj_array = AdjustedArray(data, {}, float("nan"))
  
      with self.assertRaises(WindowLengthTooLong):
          adj_array.traverse(7)
  
      with self.assertRaises(WindowLengthNotPositive):
          adj_array.traverse(0)
  
      with self.assertRaises(WindowLengthNotPositive):
          adj_array.traverse(-1)
  
imports: from collections import namedtuple
  from itertools import chain, product
  from string import ascii_lowercase, ascii_uppercase
  from textwrap import dedent
  from unittest import TestCase
  from nose_parameterized import parameterized
  from numpy import arange, array, asarray, dtype, full
  from six.moves import zip_longest
  from toolz import curry
  from zipline.errors import WindowLengthNotPositive, WindowLengthTooLong
  from zipline.lib.adjustment import Boolean1DArrayOverwrite, BooleanOverwrite, Datetime641DArrayOverwrite, Datetime64Overwrite, Float641DArrayOverwrite, Float64Multiply, Float64Overwrite, Int64Overwrite, Object1DArrayOverwrite, ObjectOverwrite
  from zipline.lib.adjusted_array import AdjustedArray
  from zipline.lib.labelarray import LabelArray
  from zipline.testing import check_arrays
  from zipline.testing.predicates import assert_equal
  from zipline.utils.compat import unicode
  from zipline.utils.numpy_utils import coerce_to_dtype, datetime64ns_dtype, default_missing_value_for_dtype, bool_dtype, float64_dtype, int64_dtype, object_dtype
label_desc: Use image node_id 7 for calling the AdjustedArrayTestCase obj's underlying member method code with example usage: obj.test_invalid_lookback() without return types