Use default rust directory structure for tests

tests/chars.rs

@@ -0,0 +1,25 @@
+extern crate rhai;
+
+use rhai::Engine;
+
+#[test]
+fn test_chars() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<char>("'y'") {
+        assert_eq!(result, 'y');
+    } else {
+        assert!(false);
+    }
+
+    if let Ok(result) = engine.eval::<char>("'\\u2764'") {
+        assert_eq!(result, '❤');
+    } else {
+        assert!(false);
+    }
+
+    match engine.eval::<char>("''") {
+        Err(_) => (),
+        _ => assert!(false),
+    }
+}