tests/install: use fifo to test stream copying

Author: DaringCuteSeal

tests/by-util/test_install.rs

@@ -1720,16 +1720,34 @@ fn test_install_root_combined() {
 
 #[test]
 #[cfg(unix)]
-fn test_install_from_pipe() {
-    let (at, mut ucmd) = at_and_ucmd!();
-    let target = "target";
-    let test_string = "Hello, World!\n";
-
-    ucmd.arg("/dev/stdin")
-        .arg(target)
-        .pipe_in(test_string)
-        .succeeds();
-
-    assert!(at.file_exists(target));
-    assert_eq!(at.read(target), test_string);
+fn test_install_from_fifo() {
+    use std::fs::OpenOptions;
+    use std::io::Write;
+    use std::thread;
+
+    let pipe_name = "pipe";
+    let target_name = "target";
+    let test_string = "Hello, world!\n";
+
+    let s = TestScenario::new(util_name!());
+    s.fixtures.mkfifo(pipe_name);
+    assert!(s.fixtures.is_fifo(pipe_name));
+
+    let proc = s.ucmd().arg(pipe_name).arg(target_name).run_no_wait();
+
+    let pipe_path = s.fixtures.plus(pipe_name);
+    let thread = thread::spawn(move || {
+        let mut pipe = OpenOptions::new()
+            .write(true)
+            .create(false)
+            .open(pipe_path)
+            .unwrap();
+        pipe.write_all(test_string.as_bytes()).unwrap();
+    });
+
+    proc.wait().unwrap();
+    thread.join().unwrap();
+
+    assert!(s.fixtures.file_exists(target_name));
+    assert_eq!(s.fixtures.read(target_name), test_string);
 }