use local library source instead to correct some black-box issue for aliyuniot

lib/ArduinoJson/extras/tests/ElementProxy/add.cpp

@@ -0,0 +1,26 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2020
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using namespace ARDUINOJSON_NAMESPACE;
+
+TEST_CASE("ElementProxy::add()") {
+  DynamicJsonDocument doc(4096);
+  doc.addElement();
+  ElementProxy<JsonDocument&> ep = doc[0];
+
+  SECTION("add(int)") {
+    ep.add(42);
+
+    REQUIRE(doc.as<std::string>() == "[[42]]");
+  }
+
+  SECTION("add(const char*)") {
+    ep.add("world");
+
+    REQUIRE(doc.as<std::string>() == "[[\"world\"]]");
+  }
+}