JsonArray::remove() and JsonObject::remove() now release the memory of strings

test/DynamicMemoryPool/allocString.cpp

@@ -0,0 +1,28 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson/Memory/DynamicMemoryPool.hpp>
+#include <catch.hpp>
+#include <sstream>
+
+using namespace ARDUINOJSON_NAMESPACE;
+
+TEST_CASE("DynamicMemoryPool::allocFrozenString()") {
+  DynamicMemoryPool pool;
+
+  SECTION("Returns different pointers") {
+    StringSlot* a = pool.allocFrozenString(1);
+    StringSlot* b = pool.allocFrozenString(2);
+    REQUIRE(a != b);
+    REQUIRE(a->value != b->value);
+  }
+
+  SECTION("Returns same slot after freeString") {
+    StringSlot* a = pool.allocFrozenString(1);
+    pool.freeString(a);
+    StringSlot* b = pool.allocFrozenString(2);
+    REQUIRE(a == b);
+    REQUIRE(a->value == b->value);
+  }
+}