Added BasicJsonDocument to support custom allocator (issue #876)

test/JsonDocument/BasicJsonDocument.cpp

@@ -0,0 +1,49 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <stdlib.h>  // malloc, free
+#include <catch.hpp>
+#include <sstream>
+
+using ARDUINOJSON_NAMESPACE::addPadding;
+
+class SpyingAllocator {
+ public:
+  SpyingAllocator(std::ostream& log) : _log(log) {}
+
+  void* allocate(size_t n) {
+    _log << "A" << n;
+    return malloc(n);
+  }
+  void deallocate(void* p) {
+    _log << "F";
+    free(p);
+  }
+
+ private:
+  SpyingAllocator& operator=(const SpyingAllocator& src);
+
+  std::ostream& _log;
+};
+
+typedef BasicJsonDocument<SpyingAllocator> MyJsonDocument;
+
+TEST_CASE("BasicJsonDocument") {
+  std::stringstream log;
+
+  SECTION("Construct/Destruct") {
+    { MyJsonDocument doc(4096, log); }
+    REQUIRE(log.str() == "A4096F");
+  }
+
+  SECTION("Copy construct") {
+    {
+      MyJsonDocument doc1(4096, log);
+      doc1.set(std::string("The size of this string is 32!!"));
+      MyJsonDocument doc2(doc1);
+    }
+    REQUIRE(log.str() == "A4096A32FF");
+  }
+}