Added JsonVariant::clear()

test/MemberProxy/clear.cpp

@@ -0,0 +1,27 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using namespace ARDUINOJSON_NAMESPACE;
+
+TEST_CASE("MemberProxy::clear()") {
+  DynamicJsonDocument doc(4096);
+  MemberProxy<JsonDocument&, const char*> mp = doc["hello"];
+
+  SECTION("size goes back to zero") {
+    mp.add(42);
+    mp.clear();
+
+    REQUIRE(mp.size() == 0);
+  }
+
+  SECTION("isNull() return true") {
+    mp.add("hello");
+    mp.clear();
+
+    REQUIRE(mp.isNull() == true);
+  }
+}