Added support for non zero-terminated strings (fixes #704)

test/JsonDeserializer/std_string.cpp

@@ -0,0 +1,35 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2018
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("deserializeJson(const std::string&)") {
+  DynamicJsonDocument doc;
+
+  SECTION("should accept const string") {
+    const std::string input("[42]");
+
+    JsonError err = deserializeJson(doc, input);
+
+    REQUIRE(err == JsonError::Ok);
+  }
+
+  SECTION("should accept temporary string") {
+    JsonError err = deserializeJson(doc, std::string("[42]"));
+
+    REQUIRE(err == JsonError::Ok);
+  }
+
+  SECTION("should duplicate content") {
+    std::string input("[\"hello\"]");
+
+    JsonError err = deserializeJson(doc, input);
+    input[2] = 'X';  // alter the string tomake sure we made a copy
+
+    JsonArray &array = doc.as<JsonArray>();
+    REQUIRE(err == JsonError::Ok);
+    REQUIRE(std::string("hello") == array[0]);
+  }
+}