add missing lib

lib/ArduinoJson/test/Misc/StringTraits.cpp

@@ -0,0 +1,22 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using namespace ArduinoJson::Internals;
+
+template <typename String>
+bool should_duplicate() {
+  return StringTraits<String>::should_duplicate;
+}
+
+TEST_CASE("StringTraits") {
+  SECTION("should_duplicate") {
+    REQUIRE(false == should_duplicate<const char*>());
+    REQUIRE(true == should_duplicate<char*>());
+    REQUIRE(true == should_duplicate<RawJsonString<char*> >());
+    REQUIRE(false == should_duplicate<RawJsonString<const char*> >());
+  }
+}