tail: test -f with no files

tests/fixtures/tail/follow_stdin.expected

@@ -0,0 +1,10 @@
+dos
+tres
+quattro
+cinco
+seis
+siette
+ocho
+nueve
+diez
+once

tests/test_tail.rs

@@ -2,7 +2,7 @@ extern crate uu_tail;
 
 use common::util::*;
 use std::char::from_digit;
-use std::io::{Read, Write};
+use std::io::Write;
 use uu_tail::parse_size;
 
 static UTIL_NAME: &'static str = "tail";
@@ -77,6 +77,17 @@ fn test_follow_multiple() {
     child.kill().unwrap();
 }
 
+#[test]
+fn test_follow_stdin() {
+    let (at, mut ucmd) = testing(UTIL_NAME);
+    let mut child = ucmd.arg("-f").pipe_in(at.read(FOOBAR_TXT)).run_no_wait();
+
+    let expected = at.read("follow_stdin.expected");
+    assert_eq!(read_size(&mut child, expected.len()), expected);
+
+    child.kill().unwrap();
+}
+
 #[test]
 fn test_single_big_args() {
     const FILE: &'static str = "single_big_args.txt";