ls: Fix device display (#2855)

tests/by-util/test_ls.rs

@@ -56,8 +56,70 @@ fn test_ls_ordering() {
         .stdout_matches(&Regex::new("some-dir1:\\ntotal 0").unwrap());
 }
 
+//#[cfg(all(feature = "mknod"))]
+#[test]
+fn test_ls_devices() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+    at.mkdir("some-dir1");
+
+    // Regex tests correct device ID and correct (no pad) spacing for a single file
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
+    {
+        scene
+            .ucmd()
+            .arg("-al")
+            .arg("/dev/null")
+            .succeeds()
+            .stdout_matches(&Regex::new("[^ ] 3, 2 [^ ]").unwrap());
+    }
+
+    #[cfg(target_os = "linux")]
+    {
+        scene
+            .ucmd()
+            .arg("-al")
+            .arg("/dev/null")
+            .succeeds()
+            .stdout_matches(&Regex::new("[^ ] 1, 3 [^ ]").unwrap());
+    }
+
+    // Regex tests alignment against a file (stdout is a link to a tty)
+    #[cfg(unix)]
+    {
+        let res = scene
+            .ucmd()
+            .arg("-alL")
+            .arg("/dev/null")
+            .arg("/dev/stdout")
+            .succeeds();
+
+        let null_len = String::from_utf8(res.stdout().to_owned())
+            .ok()
+            .unwrap()
+            .lines()
+            .next()
+            .unwrap()
+            .strip_suffix("/dev/null")
+            .unwrap()
+            .len();
+
+        let stdout_len = String::from_utf8(res.stdout().to_owned())
+            .ok()
+            .unwrap()
+            .lines()
+            .nth(1)
+            .unwrap()
+            .strip_suffix("/dev/stdout")
+            .unwrap()
+            .len();
+
+        assert_eq!(stdout_len, null_len);
+    }
+}
+
+#[cfg(all(feature = "chmod"))]
 #[test]
-#[cfg(feature = "chmod")]
 fn test_ls_io_errors() {
     let scene = TestScenario::new(util_name!());
     let at = &scene.fixtures;