Added JsonDocument::size()

test/JsonDocument/size.cpp

@@ -0,0 +1,28 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonDocument::size()") {
+  DynamicJsonDocument doc(4096);
+
+  SECTION("returns 0") {
+    REQUIRE(doc.size() == 0);
+  }
+
+  SECTION("as an array, return 2") {
+    doc.add(1);
+    doc.add(2);
+
+    REQUIRE(doc.size() == 2);
+  }
+
+  SECTION("as an object, return 2") {
+    doc["a"] = 1;
+    doc["b"] = 2;
+
+    REQUIRE(doc.size() == 2);
+  }
+}