Moved ancillary files to extras/ (fixes #1011)

extras/tests/JsonDocument/add.cpp

@@ -0,0 +1,22 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonDocument::add()") {
+  DynamicJsonDocument doc(4096);
+
+  SECTION("integer") {
+    doc.add(42);
+
+    REQUIRE(doc.as<std::string>() == "[42]");
+  }
+
+  SECTION("const char*") {
+    doc.add("hello");
+
+    REQUIRE(doc.as<std::string>() == "[\"hello\"]");
+  }
+}