test(ls): add more tests

tests/by-util/test_ls.rs

@@ -11,6 +11,40 @@ fn test_ls_ls_i() {
     new_ucmd!().arg("-il").succeeds();
 }
 
+#[test]
+fn test_ls_non_existing() {
+    new_ucmd!().arg("doesntexist").fails();
+}
+
+#[test]
+fn test_ls_files_dirs() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+    at.mkdir("a");
+    at.mkdir("a/b");
+    at.mkdir("a/b/c");
+    at.mkdir("z");
+    at.touch(&at.plus_as_string("a/a"));
+    at.touch(&at.plus_as_string("a/b/b"));
+
+    scene.ucmd().arg("a").succeeds();
+    scene.ucmd().arg("a/a").succeeds();
+    scene.ucmd().arg("a").arg("z").succeeds();
+
+    let result = scene.ucmd().arg("doesntexist").fails();
+    // Doesn't exist
+    assert!(result
+        .stderr
+        .contains("error: 'doesntexist': No such file or directory"));
+
+    let result = scene.ucmd().arg("a").arg("doesntexist").fails();
+    // One exists, the other doesn't
+    assert!(result
+        .stderr
+        .contains("error: 'doesntexist': No such file or directory"));
+    assert!(result.stdout.contains("a:"));
+}
+
 #[test]
 fn test_ls_ls_color() {
     new_ucmd!().arg("--color").succeeds();