add ref and & test

single_file_tests/ref_n_and.rs

@@ -0,0 +1,17 @@
+
+
+// ref: https://users.rust-lang.org/t/ref-keyword-versus/18818/4
+
+
+fn main() {
+    let ref x = 1;
+    let x2 = &1;
+
+    let &y = x;
+    let y2 = *x2;
+
+
+    println!("{} {}", x, x2);
+    println!("{} {}", y, y2);
+}
+