code: def test_all_strings_no_nulls(df):
      """
      Test `complete` output when *columns
      is all strings and `df` is unique.
      """
      cols = ["names", "numbers"]
      df = df.assign(dummy=1, names=[*ascii_lowercase[: len(df)]])
      result = df.complete(*cols, sort=True)
      columns = df.columns
      expected = (
          df.set_index(cols)  # noqa: PD013, PD010
          .unstack(cols[-1])  # noqa: PD010
          .stack(dropna=False)  # noqa: PD013
          .reset_index()
          .reindex(columns=columns)
      )
  
      assert_frame_equal(result, expected)
  
imports: from string import ascii_lowercase
  import numpy
  import pandas
  import pytest
  from hypothesis import given, settings
  from pandas.testing import assert_frame_equal
  from janitor.testing_utils.strategies import categoricaldf_strategy
label_desc: Use image node_id 20 for calling a global function with example usage: test_all_strings_no_nulls(df) without return types