Renamed undocumented function isUndefined() to isUnbound()

extras/tests/JsonArray/unbound.cpp

@@ -0,0 +1,35 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+using namespace Catch::Matchers;
+
+TEST_CASE("Unbound JsonArray") {
+  JsonArray array;
+
+  SECTION("SubscriptFails") {
+    REQUIRE(array[0].isNull());
+  }
+
+  SECTION("AddFails") {
+    array.add(1);
+    REQUIRE(0 == array.size());
+  }
+
+  SECTION("CreateNestedArrayFails") {
+    REQUIRE(array.createNestedArray().isNull());
+  }
+
+  SECTION("CreateNestedObjectFails") {
+    REQUIRE(array.createNestedObject().isNull());
+  }
+
+  SECTION("PrintToWritesBrackets") {
+    char buffer[32];
+    serializeJson(array, buffer, sizeof(buffer));
+    REQUIRE_THAT(buffer, Equals("null"));
+  }
+}