Use default rust directory structure for tests

tests/bool_op.rs

@@ -0,0 +1,25 @@
+extern crate rhai;
+
+use rhai::Engine;
+
+#[test]
+fn test_bool_op1() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<bool>("true && (false || true)") {
+        assert_eq!(result, true);
+    } else {
+        assert!(false);
+    }
+}
+
+#[test]
+fn test_bool_op2() {
+    let mut engine = Engine::new();
+
+    if let Ok(result) = engine.eval::<bool>("false && (false || true)") {
+        assert_eq!(result, false);
+    } else {
+        assert!(false);
+    }
+}