feat: start loading some stuff async

tests/jobs_tests.cpp

@@ -1,9 +1,12 @@
 #include <atomic>
 #include <chrono>
+#include <filesystem>
+#include <fstream>
 #include <stdexcept>
 #include <thread>
 #include <vector>
 
+#include <destrum/Serialization/SceneSerializer.h>
 #include <destrum/Threading/JobSystem.h>
 
 #include "TestUtils.h"
@@ -143,6 +146,21 @@ namespace {
         check(!Jobs().IsRunning(), "job system should be stopped");
     }
 
+    void testLoadSceneFileAsync()
+    {
+        Jobs().Init(2);
+        const auto path = std::filesystem::temp_directory_path() / "destrum_async_scene.json";
+        std::ofstream{path} << R"({"version":2,"name":"async","objects":[]})";
+
+        auto good = SceneSerializer::LoadSceneFileAsync(path);
+        auto missing = SceneSerializer::LoadSceneFileAsync(path.parent_path() / "destrum_no_such_scene.json");
+        check(good.get().success, "async scene load should parse a valid file");
+        check(!missing.get().success, "async scene load should report a missing file");
+
+        std::filesystem::remove(path);
+        Jobs().Shutdown();
+    }
+
     void testRunsInlineWhenStopped()
     {
         check(!Jobs().IsRunning(), "job system should start stopped");
@@ -164,4 +182,5 @@ void RunJobsTests()
     testAsyncRethrows();
     testMainThreadQueue();
     testShutdownDrainsPendingJobs();
+    testLoadSceneFileAsync();
 }