code: def test_add_column_scalar(df):
      """Checks `add_column` works as expected when adding a numeric scalar
      to the column"""
      # column appears in DataFrame
      df = df.add_column("fortytwo", 42)
      assert "fortytwo" in df.columns
  
      # values are correct in dataframe for scalar
      series = pd.Series([42] * len(df))
      series.name = "fortytwo"
      assert_series_equal(df["fortytwo"], series)
  
file_path: pyjanitor/tests/functions/test_add_column.py
imports: import numpy
  import pandas
  import pytest
  from hypothesis import given, settings
  from hypothesis import strategies
  from pandas.testing import assert_series_equal
  from janitor.testing_utils.strategies import df_strategy
label_desc: Use image node_id 5 for calling a global function with example usage: test_add_column_scalar(df) without return types