on freebsd/zfs chflags will fail, skip

test/bsd.lua

@@ -89,7 +89,9 @@ test.filesystem_bsd = {
   test_chflags = function()
     local fd = assert(S.creat(tmpfile, "RWXU"))
     assert(fd:write("append"))
-    assert(S.chflags(tmpfile, "uf_append"))
+    local ok, err = S.chflags(tmpfile, "uf_append")
+    if not ok and err.OPNOTSUPP then error "skipped" end
+    assert(ok, err)
     assert(fd:write("append"))
     assert(fd:seek(0, "set"))
     local n, err = fd:write("not append")
@@ -102,7 +104,9 @@ test.filesystem_bsd = {
     if not S.lchflags then error "skipped" end
     local fd = assert(S.creat(tmpfile, "RWXU"))
     assert(fd:write("append"))
-    assert(S.lchflags(tmpfile, "uf_append"))
+    local ok, err = S.lchflags(tmpfile, "uf_append")
+    if not ok and err.OPNOTSUPP then error "skipped" end
+    assert(ok, err)
     assert(fd:write("append"))
     assert(fd:seek(0, "set"))
     local n, err = fd:write("not append")
@@ -114,7 +118,9 @@ test.filesystem_bsd = {
   test_fchflags = function()
     local fd = assert(S.creat(tmpfile, "RWXU"))
     assert(fd:write("append"))
-    assert(fd:chflags("uf_append"))
+    local ok, err = fd:chflags("uf_append")
+    if not ok and err.OPNOTSUPP then error "skipped" end
+    assert(ok, err)
     assert(fd:write("append"))
     assert(fd:seek(0, "set"))
     local n, err = fd:write("not append")
@@ -127,7 +133,9 @@ test.filesystem_bsd = {
     if not S.chflagsat then error "skipped" end
     local fd = assert(S.creat(tmpfile, "RWXU"))
     assert(fd:write("append"))
-    assert(S.chflagsat("fdcwd", tmpfile, "uf_append", "symlink_nofollow"))
+    local ok, err = S.chflagsat("fdcwd", tmpfile, "uf_append", "symlink_nofollow")
+    if not ok and err.OPNOTSUPP then error "skipped" end
+    assert(ok, err)
     assert(fd:write("append"))
     assert(fd:seek(0, "set"))
     local n, err = fd:write("not append")