code: def test_size_on_categorical(as_index):
      df = DataFrame([[1, 1], [2, 2]], columns=["A", "B"])
      df["A"] = df["A"].astype("category")
      result = df.groupby(
          ["A", "B"], as_index=as_index, observed=False
      ).size()
  
      expected = DataFrame(
          [[1, 1, 1], [1, 2, 0], [2, 1, 0], [2, 2, 1]],
          columns=["A", "B", "size"],
      )
      expected["A"] = expected["A"].astype("category")
      if as_index:
          expected = expected.set_index(["A", "B"])["size"].rename(None)
  
      tm.assert_equal(result, expected)
  
file_path: pandas/pandas/tests/groupby/methods/test_size.py
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas.core.dtypes.common import is_integer_dtype
  from pandas import DataFrame, Index, PeriodIndex, Series
  import pandas._testing
label_desc: Use image node_id 7 for calling a global function with example usage: test_size_on_categorical(as_index) without return types