diff --git a/vfs/vfstest/write.go b/vfs/vfstest/write.go
index 03ad7bfa1..d01797f2f 100644
--- a/vfs/vfstest/write.go
+++ b/vfs/vfstest/write.go
@@ -5,6 +5,7 @@ import (
 	"runtime"
 	"testing"
 
+	"github.com/rclone/rclone/vfs"
 	"github.com/rclone/rclone/vfs/vfscommon"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -15,7 +16,7 @@ func TestWriteFileNoWrite(t *testing.T) {
 	run.skipIfNoFUSE(t)
 
 	fd, err := osCreate(run.path("testnowrite"))
-	assert.NoError(t, err)
+	require.NoError(t, err)
 
 	err = fd.Close()
 	assert.NoError(t, err)
@@ -110,6 +111,9 @@ func TestWriteFileDup(t *testing.T) {
 
 	var dupFd uintptr
 	dupFd, err = writeTestDup(fh.Fd())
+	if err == vfs.ENOSYS {
+		t.Skip("dup not supported on this platform")
+	}
 	require.NoError(t, err)
 
 	dupFile := os.NewFile(dupFd, fh.Name())
diff --git a/vfs/vfstest/write_other.go b/vfs/vfstest/write_other.go
new file mode 100644
index 000000000..762774c1a
--- /dev/null
+++ b/vfs/vfstest/write_other.go
@@ -0,0 +1,20 @@
+// +build !linux,!darwin,!freebsd,!openbsd,!windows
+
+package vfstest
+
+import (
+	"runtime"
+	"testing"
+
+	"github.com/rclone/rclone/vfs"
+)
+
+// TestWriteFileDoubleClose tests double close on write
+func TestWriteFileDoubleClose(t *testing.T) {
+	t.Skip("not supported on " + runtime.GOOS)
+}
+
+// writeTestDup performs the platform-specific implementation of the dup() syscall
+func writeTestDup(oldfd uintptr) (uintptr, error) {
+	return oldfd, vfs.ENOSYS
+}
diff --git a/vfs/vfstest/write_unix.go b/vfs/vfstest/write_unix.go
index 1c51d142a..3cf397d67 100644
--- a/vfs/vfstest/write_unix.go
+++ b/vfs/vfstest/write_unix.go
@@ -1,4 +1,4 @@
-// +build linux darwin freebsd
+// +build linux darwin freebsd openbsd
 
 package vfstest
 
@@ -8,6 +8,7 @@ import (
 
 	"github.com/rclone/rclone/vfs/vfscommon"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"golang.org/x/sys/unix"
 )
 
@@ -20,7 +21,7 @@ func TestWriteFileDoubleClose(t *testing.T) {
 	}
 
 	out, err := osCreate(run.path("testdoubleclose"))
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	fd := out.Fd()
 
 	fd1, err := unix.Dup(int(fd))
diff --git a/vfs/vfstest/write_non_unix.go b/vfs/vfstest/write_windows.go
similarity index 94%
rename from vfs/vfstest/write_non_unix.go
rename to vfs/vfstest/write_windows.go
index dc07983a4..ea04232ed 100644
--- a/vfs/vfstest/write_non_unix.go
+++ b/vfs/vfstest/write_windows.go
@@ -1,4 +1,4 @@
-// +build !linux,!darwin,!freebsd
+// +build windows
 
 package vfstest