code: def test_pct_change():
      configs = [
          {"periods": 1, "fill_method": None},
          {"periods": 1, "fill_method": "pad"},
          {"periods": 1, "fill_method": "ffill"},
          {"periods": 2, "fill_method": None},
          {"periods": 2, "fill_method": "pad"},
          {"periods": 2, "fill_method": "ffill"},
      ]
  
      for array, config in product(arrays, configs):
          s = Stream.source(array, dtype="float")
          w = s.pct_change(**config).rename("w")
          expected = list(pd.Series(array).pct_change(**config))
  
          print(config)
          assert_op([w], expected)
  
file_path: tensortrade/tests/tensortrade/unit/feed/api/float/test_utils.py
imports: import numpy
  import pandas
  from itertools import product
  from tensortrade.feed import Stream
  from tests.utils.ops import assert_op
label_desc: Use image node_id 6 for calling a global function with example usage: test_pct_change() without return types