uucore: process: fix exit status processing (#1743)

* uucore: process: fix exit status processing

* tests: timeout: check whether subcommand exit codes are returned

tests/by-util/test_timeout.rs

@@ -1 +1,18 @@
-// ToDO: add tests
+use crate::common::util::*;
+
+// FIXME: this depends on the system having true and false in PATH
+//        the best solution is probably to generate some test binaries that we can call for any
+//        utility that requires executing another program (kill, for instance)
+#[test]
+fn test_subcommand_retcode() {
+    new_ucmd!()
+        .arg("1")
+        .arg("true")
+        .succeeds();
+
+    new_ucmd!()
+        .arg("1")
+        .arg("false")
+        .run()
+        .status_code(1);
+}

tests/common/util.rs

@@ -69,6 +69,8 @@ pub fn repeat_str(s: &str, n: u32) -> String {
 pub struct CmdResult {
     //tmpd is used for convenience functions for asserts against fixtures
     tmpd: Option<Rc<TempDir>>,
+    /// exit status for command (if there is one)
+    pub code: Option<i32>,
     /// zero-exit from running the Command?
     /// see [`success`]
     pub success: bool,
@@ -91,6 +93,12 @@ impl CmdResult {
         Box::new(self)
     }
 
+    /// asserts that the command's exit code is the same as the given one
+    pub fn status_code(&self, code: i32) -> Box<&CmdResult> {
+        assert!(self.code == Some(code));
+        Box::new(self)
+    }
+
     /// asserts that the command resulted in empty (zero-length) stderr stream output
     /// generally, it's better to use stdout_only() instead,
     /// but you might find yourself using this function if
@@ -573,6 +581,7 @@ impl UCommand {
 
         CmdResult {
             tmpd: self.tmpd.clone(),
+            code: prog.status.code(),
             success: prog.status.success(),
             stdout: from_utf8(&prog.stdout).unwrap().to_string(),
             stderr: from_utf8(&prog.stderr).unwrap().to_string(),