readlink: test calling without args

tests/by-util/test_readlink.rs

@@ -2,11 +2,11 @@
 //
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
+//
 // spell-checker:ignore regfile
-use uutests::new_ucmd;
-use uutests::path_concat;
+
 use uutests::util::{TestScenario, get_root_path};
-use uutests::{at_and_ucmd, util_name};
+use uutests::{at_and_ucmd, new_ucmd, path_concat, util_name};
 
 static GIBBERISH: &str = "supercalifragilisticexpialidocious";
 
@@ -15,6 +15,14 @@ static NOT_A_DIRECTORY: &str = "Not a directory";
 #[cfg(windows)]
 static NOT_A_DIRECTORY: &str = "The directory name is invalid.";
 
+#[test]
+fn test_no_args() {
+    new_ucmd!()
+        .fails_with_code(1)
+        .no_stdout()
+        .stderr_contains("readlink: missing operand");
+}
+
 #[test]
 fn test_invalid_arg() {
     new_ucmd!().arg("--definitely-invalid").fails_with_code(1);