Moved ancillary files to extras/ (fixes #1011)

extras/tests/JsonObject/invalid.cpp

@@ -0,0 +1,35 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using namespace Catch::Matchers;
+
+TEST_CASE("JsonObject::invalid()") {
+  JsonObject obj;
+
+  SECTION("SubscriptFails") {
+    REQUIRE(obj["key"].isNull());
+  }
+
+  SECTION("AddFails") {
+    obj["hello"] = "world";
+    REQUIRE(0 == obj.size());
+  }
+
+  SECTION("CreateNestedArrayFails") {
+    REQUIRE(obj.createNestedArray("hello").isNull());
+  }
+
+  SECTION("CreateNestedObjectFails") {
+    REQUIRE(obj.createNestedObject("world").isNull());
+  }
+
+  SECTION("serialize to 'null'") {
+    char buffer[32];
+    serializeJson(obj, buffer, sizeof(buffer));
+    REQUIRE_THAT(buffer, Equals("null"));
+  }
+}