factor: trim also null-chars (#11182)

* fix bug #11097: factor: trim also null-chars

* for factor: add test_trim_null_chars

* test_factor: pipe_in instead of pipe_in_fixture

src/uu/factor/src/factor.rs

@@ -28,7 +28,8 @@ fn write_factors_str(
     w: &mut io::BufWriter<impl Write>,
     print_exponents: bool,
 ) -> UResult<()> {
-    let rx = num_str.trim().parse::<BigUint>();
+    let trimmed = num_str.trim_matches(|c: char| c.is_whitespace() || c == '\0');
+    let rx = trimmed.parse::<BigUint>();
     let Ok(x) = rx else {
         // return Ok(). it's non-fatal and we should try the next number.
         show_warning!("{}: {}", num_str.maybe_quote(), rx.unwrap_err());

tests/by-util/test_factor.rs

@@ -54,6 +54,15 @@ fn test_repeated_exponents() {
         .no_stderr();
 }
 
+#[test]
+fn test_trim_null_chars() {
+    new_ucmd!()
+        .pipe_in("42\0")
+        .succeeds()
+        .stdout_only("42: 2 3 7\n")
+        .no_stderr();
+}
+
 #[test]
 #[cfg(feature = "sort")]
 #[cfg(not(target_os = "android"))]