tests: add test for kill with real-time signal offsets

Author: enr0n

tests/by-util/test_kill.rs

@@ -6,6 +6,8 @@
 use regex::Regex;
 use std::os::unix::process::ExitStatusExt;
 use std::process::{Child, Command};
+#[cfg(any(target_os = "linux", target_os = "android"))]
+use uucore::signals::realtime_signal_bounds;
 use uutests::new_ucmd;
 
 // A child process the tests will try to kill.
@@ -539,3 +541,33 @@ fn test_kill_realtime_signal() {
         .succeeds();
     assert_eq!(target.wait_for_signal(), Some(libc::SIGRTMIN()));
 }
+
+#[cfg(any(target_os = "linux", target_os = "android"))]
+#[test]
+fn test_kill_with_rtmax_offset() {
+    let (_, rtmax) = realtime_signal_bounds().unwrap();
+    let sig: i32 = (rtmax as i32) - 7;
+
+    let mut target = Target::new();
+    new_ucmd!()
+        .arg("-s")
+        .arg("SIGRTMAX-7")
+        .arg(format!("{}", target.pid()))
+        .succeeds();
+    assert_eq!(target.wait_for_signal(), Some(sig));
+}
+
+#[cfg(any(target_os = "linux", target_os = "android"))]
+#[test]
+fn test_kill_with_rtmin_offset() {
+    let (rtmin, _) = realtime_signal_bounds().unwrap();
+    let sig: i32 = (rtmin as i32) + 7;
+
+    let mut target = Target::new();
+    new_ucmd!()
+        .arg("-s")
+        .arg("SIGRTMIN+7")
+        .arg(format!("{}", target.pid()))
+        .succeeds();
+    assert_eq!(target.wait_for_signal(), Some(sig));
+}