code: def test_series_groupby_value_counts_one_row(columns):
      # GH42618
      df = DataFrame(data=[range(len(columns))], columns=columns)
      dfg = df.groupby(columns[:-1])
  
      result = dfg[columns[-1]].value_counts()
      expected = df.value_counts()
  
      tm.assert_series_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas import Categorical, CategoricalIndex, DataFrame, Grouper, Index, MultiIndex, Series, date_range, to_datetime
  import pandas._testing
  from pandas.util.version import Version
label_desc: Use image node_id 6 for calling a global function with example usage: test_series_groupby_value_counts_one_row(columns) without return types