bpo-31904: skip some tests related to fifo on VxWorks (GH-23473)

On VxWork RTOS, FIFO must be created under directory "/fifos/". Some test cases related to fifo is invalid on VxWorks. So skip them.

Author: pxinwr

Lib/test/test_pathlib.py

@@ -2219,6 +2219,8 @@ def test_is_fifo_false(self):
  self.assertIs((P / 'fileA\x00').is_fifo(), False)
 
  @unittest.skipUnless(hasattr(os, "mkfifo"), "os.mkfifo() required")
+ @unittest.skipIf(sys.platform == "vxworks",
+ "fifo requires special path on VxWorks")
  def test_is_fifo_true(self):
  P = self.cls(BASE, 'myfifo')
  try:

Lib/test/test_shutil.py

@@ -683,6 +683,8 @@ def custom_cpfun(a, b):
  # Issue #3002: copyfile and copytree block indefinitely on named pipes
  @unittest.skipUnless(hasattr(os, "mkfifo"), 'requires os.mkfifo()')
  @os_helper.skip_unless_symlink
+ @unittest.skipIf(sys.platform == "vxworks",
+ "fifo requires special path on VxWorks")
  def test_copytree_named_pipe(self):
  os.mkdir(TESTFN)
  try:
@@ -1206,6 +1208,8 @@ def test_dont_copy_file_onto_symlink_to_itself(self):
 
  # Issue #3002: copyfile and copytree block indefinitely on named pipes
  @unittest.skipUnless(hasattr(os, "mkfifo"), 'requires os.mkfifo()')
+ @unittest.skipIf(sys.platform == "vxworks",
+ "fifo requires special path on VxWorks")
  def test_copyfile_named_pipe(self):
  try:
  os.mkfifo(TESTFN)

Misc/NEWS.d/next/Tests/2020-11-23-11-11-29.bpo-31904.V3sUZk.rst

@@ -0,0 +1 @@
+skip some tests related to fifo on VxWorks