internal/poll: remove outdated tests

TestFileFdsAreInitialised and TestSerialFdsAreInitialised were added
to ensure handles passed to os.NewFile were not added to the runtime
poller. This used to be problematic because the poller could crash
if an external I/O event was received (see #21172).

This is not an issue anymore since CL 482495 and #19098.

Change-Id: I292ceae27724fefe6f438a398ebfe351dd5231d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/665315
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Damien Neil <dneil@google.com>

Author: qmuntal

src/internal/poll/fd_windows_test.go

@@ -20,77 +20,6 @@ func init() {
 	poll.InitWSA()
 }
 
-// checkFileIsNotPartOfNetpoll verifies that f is not managed by netpoll.
-func checkFileIsNotPartOfNetpoll(t *testing.T, f *os.File) {
-	t.Helper()
-	sc, err := f.SyscallConn()
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := sc.Control(func(fd uintptr) {
-		// Only try to associate the file with an IOCP if the handle is opened for overlapped I/O,
-		// else the association will always fail.
-		overlapped, err := windows.IsNonblock(syscall.Handle(fd))
-		if err != nil {
-			t.Fatalf("%v fd=%v: %v", f.Name(), fd, err)
-		}
-		if overlapped {
-			// If the file is part of netpoll, then associating it with another IOCP should fail.
-			if _, err := windows.CreateIoCompletionPort(syscall.Handle(fd), 0, 0, 1); err != nil {
-				t.Fatalf("%v fd=%v: is part of netpoll, but should not be: %v", f.Name(), fd, err)
-			}
-		}
-	}); err != nil {
-		t.Fatalf("%v fd=%v: is not initialized", f.Name(), f.Fd())
-	}
-}
-
-func TestFileFdsAreInitialised(t *testing.T) {
-	t.Parallel()
-	exe, err := os.Executable()
-	if err != nil {
-		t.Fatal(err)
-	}
-	f, err := os.Open(exe)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer f.Close()
-
-	checkFileIsNotPartOfNetpoll(t, f)
-}
-
-func TestSerialFdsAreInitialised(t *testing.T) {
-	t.Parallel()
-	for _, name := range []string{"COM1", "COM2", "COM3", "COM4"} {
-		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-			h, err := syscall.CreateFile(syscall.StringToUTF16Ptr(name),
-				syscall.GENERIC_READ|syscall.GENERIC_WRITE,
-				0,
-				nil,
-				syscall.OPEN_EXISTING,
-				syscall.FILE_ATTRIBUTE_NORMAL|syscall.FILE_FLAG_OVERLAPPED,
-				0)
-			if err != nil {
-				if errno, ok := err.(syscall.Errno); ok {
-					switch errno {
-					case syscall.ERROR_FILE_NOT_FOUND,
-						syscall.ERROR_ACCESS_DENIED:
-						t.Log("Skipping: ", err)
-						return
-					}
-				}
-				t.Fatal(err)
-			}
-			f := os.NewFile(uintptr(h), name)
-			defer f.Close()
-
-			checkFileIsNotPartOfNetpoll(t, f)
-		})
-	}
-}
-
 func TestWSASocketConflict(t *testing.T) {
 	t.Parallel()
 	s, err := windows.WSASocket(syscall.AF_INET, syscall.SOCK_STREAM, syscall.IPPROTO_TCP, nil, 0, windows.WSA_FLAG_OVERLAPPED)