test: add core-mm tests

test/core-mm/streams.cpp

@@ -0,0 +1,18 @@
+#include <blue/core/stream.hpp>
+#include <blue/core/stringstream.hpp>
+#include <iostream>
+
+using namespace blue::core;
+
+int main(void)
+{
+	stream &out = stream::out();
+	out.write_fmt("Hello, %d\n", 32);
+
+	stringstream s;
+	s.write_fmt("Hello, %d\n", 64);
+
+	std::cout << s.get_ptr();
+
+	return 0;
+}