wasi: fix flaky tests (#2068)

Signed-off-by: Edoardo Vacchi <evacchi@users.noreply.github.com>

imports/wasi_snapshot_preview1/testdata/zig-cc/wasi.c

@@ -171,6 +171,11 @@ void main_nonblock(char* fpath) {
   ssize_t newLen = 0;
   while (newLen == 0) {
     newLen = read(fd, buf, sizeof(buf));
+    // If an empty string is read, newLen might be 1,
+    // causing the loop to terminate.
+    if (strlen(buf) == 0) {
+      newLen = 0;
+    }
     if (errno == EAGAIN || newLen == 0) {
       printf(".");
       nanosleep(&tim , &tim2) ;

internal/sysfs/poll_windows_test.go

@@ -34,8 +34,9 @@ func TestPoll_Windows(t *testing.T) {
 	t.Run("peekNamedPipe should report the correct state of incoming data in the pipe", func(t *testing.T) {
 		r, w, err := os.Pipe()
 		require.NoError(t, err)
+		defer r.Close()
+		defer w.Close()
 		rh := syscall.Handle(r.Fd())
-		wh := syscall.Handle(w.Fd())
 
 		// Ensure the pipe has no data.
 		n, err := peekNamedPipe(rh)
@@ -45,8 +46,8 @@ func TestPoll_Windows(t *testing.T) {
 		// Write to the channel.
 		msg, err := syscall.ByteSliceFromString("test\n")
 		require.NoError(t, err)
-		_, err = syscall.Write(wh, msg)
-		require.NoError(t, err)
+		_, err = write(w, msg)
+		require.EqualErrno(t, 0, err)
 
 		// Ensure the pipe has data.
 		n, err = peekNamedPipe(rh)
@@ -132,7 +133,10 @@ func TestPoll_Windows(t *testing.T) {
 	})
 
 	t.Run("poll should return immediately when duration is zero (no data)", func(t *testing.T) {
-		r, _, err := os.Pipe()
+		r, w, err := os.Pipe()
+		defer r.Close()
+		defer w.Close()
+
 		require.NoError(t, err)
 		fds := []pollFd{{fd: r.Fd(), events: _POLLIN}}
 		n, err := _poll(fds, 0)
@@ -143,14 +147,15 @@ func TestPoll_Windows(t *testing.T) {
 	t.Run("poll should return immediately when duration is zero (data)", func(t *testing.T) {
 		r, w, err := os.Pipe()
 		require.NoError(t, err)
+		defer r.Close()
+		defer w.Close()
 		fds := []pollFd{{fd: r.Fd(), events: _POLLIN}}
-		wh := syscall.Handle(w.Fd())
 
 		// Write to the channel immediately.
 		msg, err := syscall.ByteSliceFromString("test\n")
 		require.NoError(t, err)
-		_, err = syscall.Write(wh, msg)
-		require.NoError(t, err)
+		_, err = write(w, msg)
+		require.EqualErrno(t, 0, err)
 
 		// Verify that the write is reported.
 		n, err := _poll(fds, 0)
@@ -159,8 +164,10 @@ func TestPoll_Windows(t *testing.T) {
 	})
 
 	t.Run("poll should wait forever when duration is nil (no writes)", func(t *testing.T) {
-		r, _, err := os.Pipe()
+		r, w, err := os.Pipe()
 		require.NoError(t, err)
+		defer r.Close()
+		defer w.Close()
 
 		ch := make(chan result, 1)
 		go pollToChannel(r.Fd(), -1, ch)
@@ -173,7 +180,8 @@ func TestPoll_Windows(t *testing.T) {
 	t.Run("poll should wait forever when duration is nil", func(t *testing.T) {
 		r, w, err := os.Pipe()
 		require.NoError(t, err)
-		wh := syscall.Handle(w.Fd())
+		defer r.Close()
+		defer w.Close()
 
 		ch := make(chan result, 1)
 		go pollToChannel(r.Fd(), -1, ch)
@@ -185,8 +193,8 @@ func TestPoll_Windows(t *testing.T) {
 		// Write a message to the pipe.
 		msg, err := syscall.ByteSliceFromString("test\n")
 		require.NoError(t, err)
-		_, err = syscall.Write(wh, msg)
-		require.NoError(t, err)
+		_, err = write(w, msg)
+		require.EqualErrno(t, 0, err)
 
 		// Ensure that the write occurs (panic after an arbitrary timeout).
 		select {
@@ -201,7 +209,8 @@ func TestPoll_Windows(t *testing.T) {
 	t.Run("poll should wait for the given duration", func(t *testing.T) {
 		r, w, err := os.Pipe()
 		require.NoError(t, err)
-		wh := syscall.Handle(w.Fd())
+		defer r.Close()
+		defer w.Close()
 
 		ch := make(chan result, 1)
 		go pollToChannel(r.Fd(), 500, ch)
@@ -213,8 +222,8 @@ func TestPoll_Windows(t *testing.T) {
 		// Write a message to the pipe.
 		msg, err := syscall.ByteSliceFromString("test\n")
 		require.NoError(t, err)
-		_, err = syscall.Write(wh, msg)
-		require.NoError(t, err)
+		_, err = write(w, msg)
+		require.EqualErrno(t, 0, err)
 
 		// Ensure that the write occurs before the timer expires.
 		select {
@@ -227,8 +236,10 @@ func TestPoll_Windows(t *testing.T) {
 	})
 
 	t.Run("poll should timeout after the given duration", func(t *testing.T) {
-		r, _, err := os.Pipe()
+		r, w, err := os.Pipe()
 		require.NoError(t, err)
+		defer r.Close()
+		defer w.Close()
 
 		ch := make(chan result, 1)
 		go pollToChannel(r.Fd(), 200, ch)
@@ -242,7 +253,8 @@ func TestPoll_Windows(t *testing.T) {
 	t.Run("poll should return when a write occurs before the given duration", func(t *testing.T) {
 		r, w, err := os.Pipe()
 		require.NoError(t, err)
-		wh := syscall.Handle(w.Fd())
+		defer r.Close()
+		defer w.Close()
 
 		ch := make(chan result, 1)
 		go pollToChannel(r.Fd(), 800, ch)
@@ -252,8 +264,8 @@ func TestPoll_Windows(t *testing.T) {
 
 		msg, err := syscall.ByteSliceFromString("test\n")
 		require.NoError(t, err)
-		_, err = syscall.Write(wh, msg)
-		require.NoError(t, err)
+		_, err = write(w, msg)
+		require.EqualErrno(t, 0, err)
 
 		res := <-ch
 		require.Zero(t, res.err)
@@ -262,7 +274,9 @@ func TestPoll_Windows(t *testing.T) {
 
 	t.Run("poll should return when a regular file is given", func(t *testing.T) {
 		f, err := os.CreateTemp(t.TempDir(), "ex")
+		require.NoError(t, err)
 		defer f.Close()
+
 		require.NoError(t, err)
 		fds := []pollFd{{fd: f.Fd(), events: _POLLIN}}
 		n, errno := _poll(fds, 0)