code: def test_window(self):
      input = [range(1), range(2), range(3), range(4), range(5)]
  
      def func(dstream):
          return dstream.window(1.5, 0.5).count()
  
      expected = [[1], [3], [6], [9], [12], [9], [5]]
      self._test_func(input, func, expected)
  
imports: import operator
  import os
  import shutil
  import tempfile
  import time
  import unittest
  from functools import reduce
  from itertools import chain
  import platform
  from pyspark import SparkConf, SparkContext
  from pyspark.streaming import StreamingContext
  from pyspark.testing.streamingutils import PySparkStreamingTestCase
label_desc: Use image node_id 1 for calling the WindowFunctionTests obj's underlying member method code with example usage: obj.test_window() and returns: dstream