Merge pull request #4271 from eds-collabora/eds/nice

Support legacy argument syntax for nice

tests/by-util/test_nice.rs

@@ -63,3 +63,22 @@ fn test_command_where_command_takes_n_flag() {
 fn test_invalid_argument() {
     new_ucmd!().arg("--invalid").fails().code_is(125);
 }
+
+#[test]
+fn test_bare_adjustment() {
+    new_ucmd!()
+        .args(&["-1", "echo", "-n", "a"])
+        .run()
+        .stdout_is("a");
+}
+
+#[test]
+fn test_trailing_empty_adjustment() {
+    new_ucmd!()
+        .args(&["-n", "1", "-n"])
+        .fails()
+        .stderr_str()
+        .starts_with(
+        "error: The argument '--adjustment <adjustment>' requires a value but none was supplied",
+    );
+}