cut: improve function signature

and add test for existing functionality

src/uu/cut/src/cut.rs

@@ -260,9 +260,9 @@ fn cut_fields_newline_char_delim<R: Read, W: Write>(
     reader: R,
     out: &mut W,
     ranges: &[Range],
-    only_delimited: bool,
     newline_char: u8,
     out_delim: &[u8],
+    only_delimited: bool,
 ) -> UResult<()> {
     let mut reader = BufReader::new(reader);
     let mut line = Vec::new();
@@ -398,9 +398,9 @@ fn cut_fields<R: Read, W: Write>(
                 reader,
                 out,
                 ranges,
-                field_opts.only_delimited,
                 newline_char,
                 out_delim,
+                field_opts.only_delimited,
             )
         }
         Delimiter::Slice(delim) => {

tests/by-util/test_cut.rs

@@ -229,6 +229,21 @@ fn test_zero_terminated_only_delimited() {
         .stdout_only("82\n7\0");
 }
 
+#[test]
+fn test_suppresses_unterminated_segment() {
+    new_ucmd!()
+        .args(&["-z", "-d", "", "-s", "-f", "1"])
+        .pipe_in("unterminated")
+        .succeeds()
+        .stdout_only_bytes("");
+
+    new_ucmd!()
+        .args(&["-z", "-d", "", "-s", "-f", "1"])
+        .pipe_in("terminated\0unterminated")
+        .succeeds()
+        .stdout_only_bytes("terminated\0");
+}
+
 #[test]
 fn test_is_a_directory() {
     let (at, mut ucmd) = at_and_ucmd!();