stat: should fail without arguments #5928 (#5935)

* stat: should fail without arguments #5928

* style and lint issue  stat: should fail without arguments #5928

* style and lint issue  stat: should fail without arguments #5928

* style and lint 2 issue  stat: should fail without arguments #5928

---------

Co-authored-by: biplab5464 <biplab5464@outlook.com>

src/uu/stat/src/stat.rs

@@ -546,10 +546,16 @@ impl Stater {
     }
 
     fn new(matches: &ArgMatches) -> UResult<Self> {
-        let files = matches
+        let files: Vec<OsString> = matches
             .get_many::<OsString>(options::FILES)
             .map(|v| v.map(OsString::from).collect())
             .unwrap_or_default();
+        if files.is_empty() {
+            return Err(Box::new(USimpleError {
+                code: 1,
+                message: "missing operand\nTry 'stat --help' for more information.".to_string(),
+            }));
+        }
         let format_str = if matches.contains_id(options::PRINTF) {
             matches
                 .get_one::<String>(options::PRINTF)

tests/by-util/test_stat.rs

@@ -338,3 +338,10 @@ fn test_stdin_redirect() {
         .stdout_contains("File: -")
         .succeeded();
 }
+
+#[test]
+fn test_without_argument() {
+    new_ucmd!()
+        .fails()
+        .stderr_contains("missing operand\nTry 'stat --help' for more information.");
+}