Merge pull request #2486 from hbina/hbina-tr-return-err-when-extra-args

`tr` should error out when if user provides more than 2 sets

src/uu/tr/src/tr.rs

@@ -233,7 +233,7 @@ fn get_usage() -> String {
 }
 
 fn get_long_usage() -> String {
-    String::from(
+    format!(
         "Translate, squeeze, and/or delete characters from standard input,
 writing to standard output.",
     )
@@ -257,10 +257,10 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     let squeeze_flag = matches.is_present(options::SQUEEZE);
     let truncate_flag = matches.is_present(options::TRUNCATE);
 
-    let sets: Vec<String> = match matches.values_of(options::SETS) {
-        Some(v) => v.map(|v| v.to_string()).collect(),
-        None => vec![],
-    };
+    let sets = matches
+        .values_of(options::SETS)
+        .map(|v| v.map(ToString::to_string).collect::<Vec<_>>())
+        .unwrap_or_default();
 
     if sets.is_empty() {
         show_error!(
@@ -350,5 +350,11 @@ pub fn uu_app() -> App<'static, 'static> {
                 .short("t")
                 .help("first truncate SET1 to length of SET2"),
         )
-        .arg(Arg::with_name(options::SETS).multiple(true))
+        .arg(
+            Arg::with_name(options::SETS)
+                .multiple(true)
+                .takes_value(true)
+                .min_values(1)
+                .max_values(2),
+        )
 }

tests/by-util/test_tr.rs

@@ -284,3 +284,11 @@ fn test_interpret_backslash_at_eol_literally() {
         .succeeds()
         .stdout_is("\\");
 }
+
+#[test]
+fn test_more_than_2_sets() {
+    new_ucmd!()
+        .args(&["'abcdefgh'", "'a", "'b'"])
+        .pipe_in("hello world")
+        .fails();
+}