docstr: Test variable_set command with optional description argument
docstr_tok: ["Test","variable_set","command","with","optional","description","argument"]
code: def test_variables_set_with_description(self):
      """Test variable_set command with optional description argument"""
      expected_var_desc = "foo_bar_description"
      var_key = "foo"
      variable_command.variables_set(
          self.parser.parse_args(
              [
                  "variables",
                  "set",
                  var_key,
                  "bar",
                  "--description",
                  expected_var_desc,
              ]
          )
      )
  
      assert Variable.get(var_key) == "bar"
      with create_session() as session:
          actual_var_desc = session.scalar(
              select(Variable.description).where(
                  Variable.key == var_key
              )
          )
          assert actual_var_desc == expected_var_desc
  
      with pytest.raises(KeyError):
          Variable.get("foo1")
  
imports: from __future__ import annotations
  import os
  from contextlib import redirect_stdout
  from io import StringIO
  import pytest
  from sqlalchemy import select
  from airflow import models
  from airflow.cli import cli_parser
  from airflow.cli.commands import variable_command
  from airflow.models import Variable
  from airflow.utils.session import create_session
  from tests.test_utils.db import clear_db_variables
label_desc: Use image node_id 5 for calling the TestCliVariables obj's underlying member method code with example usage: obj.test_variables_set_with_description() without return types