Added 7 new test cases to test_os.py which tests the os module.

Following is a test class to test os.renames(). It starts by creating a temporary directory tree, and then renaming it. A walk is performed on the top most directory later on, and it is examined to verify that the renaming has taken place.

class RenamesDirTest(unittest.TestCase):
  def setUp(self):
      if os.path.exists(support.TESTFN):
          os.remove(support.TESTFN)
      os.mkdir(support.TESTFN)

  def test_renames(self):
      base=support.TESTFN
      self.old=os.path.join(base, "dir1", "dir2", "dir3", "dir4")
      os.makedirs(self.old)
      self.new=os.path.join(base, "dir1", "dir2", "test3", "test4")
      os.renames(self.old, self.new)
      for (dirpath, dirnames, filenames) in os.walk(base, topdown=False):
          self.assertEqual(self.new, dirpath)
          break
   
  def tearDown(self):
      if os.path.exists(self.new):
          os.removedirs(self.new)
      elif os.path.exists(self.old):
          os.removedirs(self.old)

A test for os.chdir(). Current directory for the current process is changed using os.chdir(), and later confirmed by calling os.getcwd(). A test case to see that os.chdir() fails when called with a directory argument that doesn't exist is also added.

#Tests for changing directory paths
class ChangePathTests(unittest.TestCase):
   def setUp(self):
       self.tempdir=support.TESTFN
       os.mkdir(self.tempdir)
       self.tempdir2=support.TESTFN+"2"

   def test_chdir(self):
       if os.path.exists(self.tempdir):
           os.chdir(self.tempdir)
           cwd=os.getcwd()
           self.assertEqual(cwd, self.tempdir)

   #Test to check chdir fails if nonexisting directory passed
   def test_chdir_nonexistent(self):
       if os.path.exists(self.tempdir2):
           os.rmdir(self.tempdir2)
       try:
           os.chdir(self.tempdir2)
       except OSError:
           pass
       else:
           self.fail("Did not raise OSError")

   def tearDown(self):
       if os.path.exists(self.tempdir):
           os.rmdir(self.tempdir)

A test class to test os.geteuid() and os.getgid(). Both are verified by comparing with values returned by os.stat().

class PosixGetUidGidTests(unittest.TestCase):
   def setUp(self):
       f=os.open(support.TESTFN, os.O_CREAT|os.O_RDWR)
       os.close(f)
       self.stats=os.stat(__file__)
 
   def tearDown(self):
       if os.path.exists(support.TESTFN):
           os.remove(support.TESTFN)
         
   if hasattr(os, "geteuid"):
       def test_geteuid(self):
           self.assertEqual(os.geteuid(), self.stats.st_uid)
 
   if hasattr(os, "getgid"):
       def test_getgid(self):
           self.assertEqual(os.getgid(), self.stats.st_gid)

A test class for testing os.getenv() and os.putenv().

class GetPutEnvironTests(unittest.TestCase):
   def test_putenv(self):
       try:
           os.putenv("KEY", "VALUE")
       except:
           self.fail("Not able to set environment variable")
 
   def test_getenv(self):
       keyvalue={"KEY":"VALUE"}
       os.environ["KEY"]=keyvalue["KEY"]
       value=os.getenv("KEY")
       self.assertEqual(value, keyvalue["KEY"])

I am designing a few more tests to test the os.spawn* family of functions.