Add dir and vdir utils (based on ls)

Fix issue #3163

They are basically ls with some different options.

tests/by-util/test_dir.rs

@@ -0,0 +1,55 @@
+#[cfg(not(windows))]
+extern crate libc;
+extern crate regex;
+#[cfg(not(windows))]
+extern crate tempfile;
+#[cfg(unix)]
+extern crate unix_socket;
+
+use self::regex::Regex;
+use crate::common::util::*;
+
+/*
+ * As dir use the same functions than ls, we don't have to retest them here.
+ * We just test the default and the long output
+*/
+
+#[test]
+fn test_dir() {
+    new_ucmd!().succeeds();
+}
+
+#[test]
+fn test_default_output() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+    at.mkdir("some-dir1");
+    at.touch("some-file1");
+
+    scene.ucmd().succeeds().stdout_contains("some-file1");
+
+    scene
+        .ucmd()
+        .succeeds()
+        .stdout_does_not_match(&Regex::new("[rwx][^some-file1]").unwrap());
+}
+
+#[test]
+fn test_long_output() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+    at.mkdir("some-dir1");
+    at.touch("some-file1");
+
+    scene
+        .ucmd()
+        .arg("-l")
+        .succeeds()
+        .stdout_contains("some-file1");
+
+    scene
+        .ucmd()
+        .arg("-l")
+        .succeeds()
+        .stdout_matches(&Regex::new("[rwx][^some-file1]").unwrap());
+}