Added JsonDocument::size()

test/ElementProxy/CMakeLists.txt

@@ -5,6 +5,7 @@
 add_executable(ElementProxyTests
 	add.cpp
 	set.cpp
+	size.cpp
 )
 
 target_link_libraries(ElementProxyTests catch)

test/ElementProxy/size.cpp

@@ -0,0 +1,30 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using namespace ARDUINOJSON_NAMESPACE;
+
+TEST_CASE("ElementProxy::size()") {
+  DynamicJsonDocument doc(4096);
+  doc.addElement();
+  ElementProxy<JsonDocument&> ep = doc[0];
+
+  SECTION("returns 0") {
+    REQUIRE(ep.size() == 0);
+  }
+
+  SECTION("as an array, returns 2") {
+    ep.add(1);
+    ep.add(2);
+    REQUIRE(ep.size() == 2);
+  }
+
+  SECTION("as an object, returns 2") {
+    ep["a"] = 1;
+    ep["b"] = 2;
+    REQUIRE(ep.size() == 2);
+  }
+}