bpo-40280: Skip wakeup_fd pipe tests on Emscripten (GH-31909)

Author: tiran

Lib/test/test_signal.py

@@ -205,6 +205,9 @@ def test_invalid_socket(self):
         self.assertRaises((ValueError, OSError),
                           signal.set_wakeup_fd, fd)
 
+    # Emscripten does not support fstat on pipes yet.
+    # https://github.com/emscripten-core/emscripten/issues/16414
+    @unittest.skipIf(support.is_emscripten, "Emscripten cannot fstat pipes.")
     def test_set_wakeup_fd_result(self):
         r1, w1 = os.pipe()
         self.addCleanup(os.close, r1)
@@ -222,6 +225,7 @@ def test_set_wakeup_fd_result(self):
         self.assertEqual(signal.set_wakeup_fd(-1), w2)
         self.assertEqual(signal.set_wakeup_fd(-1), -1)
 
+    @unittest.skipIf(support.is_emscripten, "Emscripten cannot fstat pipes.")
     def test_set_wakeup_fd_socket_result(self):
         sock1 = socket.socket()
         self.addCleanup(sock1.close)
@@ -241,6 +245,7 @@ def test_set_wakeup_fd_socket_result(self):
     # On Windows, files are always blocking and Windows does not provide a
     # function to test if a socket is in non-blocking mode.
     @unittest.skipIf(sys.platform == "win32", "tests specific to POSIX")
+    @unittest.skipIf(support.is_emscripten, "Emscripten cannot fstat pipes.")
     def test_set_wakeup_fd_blocking(self):
         rfd, wfd = os.pipe()
         self.addCleanup(os.close, rfd)