code: def test_str():
      assert str(Style(bold=False)) == "not bold"
      assert str(Style(color="red", bold=False)) == "not bold red"
      assert (
          str(Style(color="red", bold=False, italic=True))
          == "not bold italic red"
      )
      assert str(Style()) == "none"
      assert str(Style(bold=True)) == "bold"
      assert str(Style(color="red", bold=True)) == "bold red"
      assert (
          str(Style(color="red", bgcolor="black", bold=True))
          == "bold red on black"
      )
      all_styles = Style(
          color="red",
          bgcolor="black",
          bold=True,
          dim=True,
          italic=True,
          underline=True,
          blink=True,
          blink2=True,
          reverse=True,
          conceal=True,
          strike=True,
          underline2=True,
          frame=True,
          encircle=True,
          overline=True,
      )
      expected = "bold dim italic underline blink blink2 reverse conceal strike underline2 frame encircle overline red on black"
      assert str(all_styles) == expected
      assert str(Style(link="foo")) == "link foo"
  
imports: import pytest
  from rich import errors
  from rich.color import Color, ColorSystem, ColorType
  from rich.style import Style, StyleStack
label_desc: Use image node_id 1 for calling a global function with example usage: test_str() without return types