code: def test_imaginary():
      x = Symbol("x")
      lines = [
          "      1 |                                                     ..",
          "        |                                                   ..  ",
          "        |                                                ...    ",
          "        |                                              ..       ",
          "        |                                            ..         ",
          "        |                                          ..           ",
          "        |                                        ..             ",
          "        |                                      ..               ",
          "        |                                    ..                 ",
          "        |                                   /                   ",
          "    0.5 |----------------------------------/--------------------",
          "        |                                ..                     ",
          "        |                               /                       ",
          "        |                              .                        ",
          "        |                                                       ",
          "        |                             .                         ",
          "        |                            .                          ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "      0 |_______________________________________________________",
          "         -1                         0                          1",
      ]
      # RuntimeWarning: invalid value encountered in sqrt
      with ignore_warnings(RuntimeWarning):
          assert list(textplot_str(sqrt(x), -1, 1)) == lines
  
      lines = [
          "      1 |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "      0 |-------------------------------------------------------",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "        |                                                       ",
          "     -1 |_______________________________________________________",
          "         -1                         0                          1",
      ]
      assert list(textplot_str(S.ImaginaryUnit, -1, 1)) == lines
  
file_path: sympy/sympy/plotting/tests/test_textplot.py
imports: from sympy.core.singleton import S
  from sympy.core.symbol import Symbol
  from sympy.functions.elementary.exponential import log
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import sin
  from sympy.plotting.textplot import textplot_str
  from sympy.utilities.exceptions import ignore_warnings
label_desc: Use image node_id 4 for calling a global function with example usage: test_imaginary() without return types