code: def test_discover(self):
      loader = unittest.TestLoader()
  
      original_isfile = os.path.isfile
      original_isdir = os.path.isdir
  
      def restore_isfile():
          os.path.isfile = original_isfile
  
      os.path.isfile = lambda path: False
      self.addCleanup(restore_isfile)
  
      orig_sys_path = sys.path[:]
  
      def restore_path():
          sys.path[:] = orig_sys_path
  
      self.addCleanup(restore_path)
  
      full_path = os.path.abspath(os.path.normpath("/foo"))
      with self.assertRaises(ImportError):
          loader.discover("/foo/bar", top_level_dir="/foo")
  
      self.assertEqual(loader._top_level_dir, full_path)
      self.assertIn(full_path, sys.path)
  
      os.path.isfile = lambda path: True
      os.path.isdir = lambda path: True
  
      def restore_isdir():
          os.path.isdir = original_isdir
  
      self.addCleanup(restore_isdir)
  
      _find_tests_args = []
  
      def _find_tests(start_dir, pattern):
          _find_tests_args.append((start_dir, pattern))
          return ["tests"]
  
      loader._find_tests = _find_tests
      loader.suiteClass = str
  
      suite = loader.discover("/foo/bar/baz", "pattern", "/foo/bar")
  
      top_level_dir = os.path.abspath("/foo/bar")
      start_dir = os.path.abspath("/foo/bar/baz")
      self.assertEqual(suite, "['tests']")
      self.assertEqual(loader._top_level_dir, top_level_dir)
      self.assertEqual(_find_tests_args, [(start_dir, "pattern")])
      self.assertIn(top_level_dir, sys.path)
  
imports: import os.path
  from os.path import abspath
  import re
  import sys
  import types
  import pickle
  from test import support
  from test.support import import_helper
  import unittest
  import unittest.mock
  import test.test_unittest
label_desc: Use image node_id 7 for calling the TestDiscovery obj's underlying member method code with example usage: obj.test_discover() and returns: list