refactor to const_string

close #110

test/unit/const_string.cpp

@@ -0,0 +1,42 @@
+//
+// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/CPPAlliance/url
+//
+
+// Test that header file is self-contained.
+#include <boost/url/const_string.hpp>
+
+#include "test_suite.hpp"
+
+namespace boost {
+namespace urls {
+
+#ifdef BOOST_URL_HAS_STRING_VIEW
+BOOST_STATIC_ASSERT(is_stringlike<
+    std::string_view>::value);
+#endif
+
+class string_test
+{
+public:
+    void
+    run()
+    {
+        const_string sv("hello");
+        auto sv2 = sv;
+        BOOST_TEST(sv2 == sv);
+        sv = {};
+        BOOST_TEST(sv2 != sv);
+    }
+};
+
+TEST_SUITE(
+    string_test,
+    "boost.url.string");
+
+} // urls
+} // boost