Fixed serializeJson(obj[key], dst) (closes #794)

test/JsonSerializer/misc.cpp

@@ -0,0 +1,46 @@
+#include <ArduinoJson.h>
+#include <catch.hpp>
+#include <limits>
+
+template <typename T>
+void check(T value, const std::string &expected) {
+  DynamicJsonDocument doc;
+  doc.to<JsonVariant>().set(value);
+  char buffer[256] = "";
+  size_t returnValue = serializeJson(doc, buffer, sizeof(buffer));
+  REQUIRE(expected == buffer);
+  REQUIRE(expected.size() == returnValue);
+}
+
+TEST_CASE("serializeJson(JsonObjectSubscript)") {
+  DynamicJsonDocument doc;
+  deserializeJson(doc, "{\"hello\":42}");
+  JsonObject obj = doc.as<JsonObject>();
+  std::string result;
+
+  serializeJson(obj["hello"], result);
+
+  REQUIRE(result == "42");
+}
+
+TEST_CASE("serializeJson(JsonArraySubscript)") {
+  DynamicJsonDocument doc;
+  deserializeJson(doc, "[42]");
+  JsonArray arr = doc.as<JsonArray>();
+  std::string result;
+
+  serializeJson(arr[0], result);
+
+  REQUIRE(result == "42");
+}
+
+TEST_CASE("serializeJson(JsonVariantSubscript)") {
+  DynamicJsonDocument doc;
+  deserializeJson(doc, "[42]");
+  JsonVariant var = doc.as<JsonVariant>();
+  std::string result;
+
+  serializeJson(var[0], result);
+
+  REQUIRE(result == "42");
+}