tee: ensure that -h and --help are identical

src/uu/tee/src/tee.rs

@@ -89,6 +89,16 @@ pub fn uu_app() -> Command {
         .override_usage(format_usage(USAGE))
         .after_help(AFTER_HELP)
         .infer_long_args(true)
+        // Since we use value-specific help texts for "--output-error", clap's "short help" and "long help" differ.
+        // However, this is something that the GNU tests explicitly test for, so we *always* show the long help instead.
+        .disable_help_flag(true)
+        .arg(
+            Arg::new("--help")
+                .short('h')
+                .long("help")
+                .help("Print help")
+                .action(ArgAction::HelpLong)
+        )
         .arg(
             Arg::new(options::APPEND)
                 .long(options::APPEND)

tests/by-util/test_tee.rs

@@ -18,6 +18,22 @@ fn test_invalid_arg() {
     new_ucmd!().arg("--definitely-invalid").fails().code_is(1);
 }
 
+#[test]
+fn test_short_help_is_long_help() {
+    // I can't believe that this test is necessary.
+    let help_short = new_ucmd!()
+        .arg("-h")
+        .succeeds()
+        .no_stderr()
+        .stdout_str()
+        .to_owned();
+    new_ucmd!()
+        .arg("--help")
+        .succeeds()
+        .no_stderr()
+        .stdout_is(help_short);
+}
+
 #[test]
 fn test_tee_processing_multiple_operands() {
     // POSIX says: "Processing of at least 13 file operands shall be supported."