Add more tests for JsonObjectConst

extras/tests/JsonObjectConst/size.cpp

@@ -0,0 +1,22 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2024, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+#include <string>
+
+TEST_CASE("JsonObjectConst::size()") {
+  JsonDocument doc;
+  JsonObjectConst obj = doc.to<JsonObject>();
+
+  SECTION("returns 0 when empty") {
+    REQUIRE(0 == obj.size());
+  }
+
+  SECTION("returns the number of members") {
+    doc["hello"] = 1;
+    doc["world"] = 2;
+    REQUIRE(2 == obj.size());
+  }
+}