code: def test_open_browser():
      from dtale.app import show
      import dtale.global_state as global_state
  
      test_data = pd.DataFrame([dict(a=1, b=2)])
  
      with ExitStack() as stack:
          mock_run = stack.enter_context(
              mock.patch("dtale.app.DtaleFlask.run", mock.Mock())
          )
          stack.enter_context(
              mock.patch(
                  "dtale.app.find_free_port",
                  mock.Mock(return_value=9999),
              )
          )
          stack.enter_context(
              mock.patch(
                  "socket.gethostname",
                  mock.Mock(return_value="localhost"),
              )
          )
          stack.enter_context(
              mock.patch(
                  "dtale.app.is_up", mock.Mock(return_value=True)
              )
          )
          mock_data_loader = mock.Mock(return_value=test_data)
          mock_browser_proc = stack.enter_context(
              mock.patch("subprocess.Popen")
          )
          mock_webbrowser = stack.enter_context(
              mock.patch("webbrowser.open")
          )
          stack.enter_context(
              mock.patch(
                  "distutils.spawn.find_executable",
                  mock.Mock(return_value=None),
              )
          )
          stack.enter_context(
              mock.patch("dtale.env_util.IS_WINDOWS", False)
          )
          stack.enter_context(
              mock.patch("dtale.env_util.IS_LINUX_OR_BSD", True)
          )
          stack.enter_context(
              mock.patch("dtale.env_util.IS_DARWIN", False)
          )
          instance = show(
              data_loader=mock_data_loader,
              subprocess=False,
              port=9999,
              open_browser=True,
              ignore_duplicate=True,
          )
          mock_run.assert_not_called()
          mock_webbrowser.assert_called()
          assert mock_webbrowser.call_args[0][
              0
          ] == "http://localhost:9999/dtale/main/{}".format(
              instance._data_id
          )
          mock_browser_proc.reset_mock()
          mock_webbrowser.reset_mock()
  
          stack.enter_context(
              mock.patch(
                  "distutils.spawn.find_executable",
                  mock.Mock(return_value="exists"),
              )
          )
          instance.open_browser()
          mock_browser_proc.assert_called()
          assert mock_browser_proc.call_args[0][0][
              1
          ] == "http://localhost:9999/dtale/main/{}".format(
              instance._data_id
          )
          mock_browser_proc.reset_mock()
          mock_webbrowser.reset_mock()
  
          stack.enter_context(
              mock.patch("dtale.env_util.IS_WINDOWS", False)
          )
          stack.enter_context(
              mock.patch("dtale.env_util.IS_LINUX_OR_BSD", False)
          )
          stack.enter_context(
              mock.patch("dtale.env_util.IS_DARWIN", True)
          )
  
          instance.open_browser()
          mock_browser_proc.assert_called()
          assert mock_browser_proc.call_args[0][0][
              1
          ] == "http://localhost:9999/dtale/main/{}".format(
              instance._data_id
          )
          mock_browser_proc.reset_mock()
          mock_webbrowser.reset_mock()
  
          stack.enter_context(
              mock.patch("dtale.env_util.IS_WINDOWS", True)
          )
          stack.enter_context(
              mock.patch("dtale.env_util.IS_LINUX_OR_BSD", False)
          )
          stack.enter_context(
              mock.patch("dtale.env_util.IS_DARWIN", False)
          )
  
          instance.open_browser()
          mock_webbrowser.assert_called()
          assert mock_webbrowser.call_args[0][
              0
          ] == "http://localhost:9999/dtale/main/{}".format(
              instance._data_id
          )
  
      global_state.cleanup()
  
imports: import getpass
  from collections import namedtuple
  from flask import Flask
  import mock
  import numpy
  import os
  import pandas
  import pytest
  from tests import ExitStack, pdt
label_desc: Use image node_id 4 for calling a global function with example usage: test_open_browser() without return types