Add more tests.

tests/callback_function.aer

@@ -0,0 +1,15 @@
+class Program {
+
+	function main(string[] $args) {
+		callback $y = function() {
+			callback $a = 'printf';
+			$a("I'm alive\n");
+			var_dump($a);
+		};
+		$y();
+		var_dump($y);
+		string $a = 'printf';
+		var_dump($a);
+	}
+
+}

tests/callback_function.exp

@@ -0,0 +1,4 @@
+I'm alive
+callback(6 'printf')
+callback(11 '{closure_1}')
+string(6 'printf')

tests/reference_test.aer

@@ -0,0 +1,13 @@
+class Program {
+
+	function add_by_ref(int &$val) {
+		$val += 7;
+	}
+
+	function main() {
+		int $num = 7;
+		$this->add_by_ref($num);
+		var_dump($num);
+	}
+
+}

tests/reference_test.exp

@@ -0,0 +1 @@
+int(14)