test_tail: add test_retry5

tests/by-util/test_tail.rs

@@ -645,6 +645,40 @@ fn test_retry4() {
     }
 }
 
+#[test]
+#[cfg(target_os = "linux")] // FIXME: fix this test for BSD/macOS
+fn test_retry5() {
+    // gnu/tests/tail-2/retry.sh
+    // Ensure that `tail --follow=descriptor --retry` exits when the file appears untailable.
+
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+    let missing = "missing";
+
+    let expected_stderr = "tail: warning: --retry only effective for the initial open\n\
+                           tail: cannot open 'missing' for reading: No such file or directory\n\
+                           tail: 'missing' has been replaced with an untailable file; giving up on this name\n\
+                           tail: no files remaining\n";
+    let delay = 1000;
+    let mut args = vec!["--follow=descriptor", "--retry", missing, "--use-polling"];
+    for _ in 0..2 {
+        let mut p = ts.ucmd().args(&args).run_no_wait();
+
+        sleep(Duration::from_millis(delay));
+        at.mkdir(missing);
+        sleep(Duration::from_millis(delay));
+
+        p.kill().unwrap();
+
+        let (buf_stdout, buf_stderr) = take_stdout_stderr(&mut p);
+        assert!(buf_stdout.is_empty());
+        assert_eq!(buf_stderr, expected_stderr);
+
+        at.rmdir(missing);
+        args.pop();
+    }
+}
+
     // gnu/tests/tail-2/descriptor-vs-rename.sh
     let ts = TestScenario::new(util_name!());
     let at = &ts.fixtures;