code: def test_format_string(styler):
      ctx = styler.format("{:.2f}")._translate(True, True)
      assert ctx["body"][0][1]["display_value"] == "0.00"
      assert ctx["body"][0][2]["display_value"] == "-0.61"
      assert ctx["body"][1][1]["display_value"] == "1.00"
      assert ctx["body"][1][2]["display_value"] == "-1.23"
  
imports: import numpy
  import pytest
  from pandas import NA, DataFrame, IndexSlice, MultiIndex, NaT, Timestamp, option_context
  from pandas.io.formats.style import Styler
  from pandas.io.formats.style_render import _str_escape
label_desc: Use image node_id 9 for calling a global function with example usage: test_format_string(styler) without return types