Add callable test

Author: audiobird

tests/callable_tests.cc

@@ -0,0 +1,15 @@
+#include "doctest.h"
+#include "util/callable.hh"
+
+TEST_CASE("Callable Function") {
+	auto capture{0};
+	auto func = Function<int(int, int)>{[&capture](int a, int b) {
+		capture += 10;
+		return a + b + capture;
+	}};
+
+	CHECK(func(10, 10) == 30);
+	CHECK(capture == 10);
+	CHECK(func(10, 10) == 40);
+	CHECK(capture == 20);
+}