add unit tests

saveload fixes

run_tests.bat

@@ -0,0 +1,90 @@
+@echo off
+setlocal enabledelayedexpansion
+
+echo Automated Test Suite Runner
+echo ============================
+echo.
+echo Scanning for test files in tests\ directory...
+
+set total_tests=0
+set failed_tests=0
+
+echo.
+echo Discovered test files:
+
+call :discover_tests "tests" ""
+call :discover_tests "tests\unit" "Unit: "
+call :discover_tests "tests\integration" "Integration: "
+
+echo.
+echo Starting test execution...
+echo.
+
+call :run_tests "tests" ""
+call :run_tests "tests\unit" "Unit: "
+call :run_tests "tests\integration" "Integration: "
+
+set /a passed_tests=total_tests-failed_tests
+
+echo ================================
+echo Test Execution Summary
+echo ================================
+echo Total Tests Run: !total_tests!
+echo Tests Passed: !passed_tests!
+echo Tests Failed: !failed_tests!
+
+if !failed_tests! equ 0 (
+    echo ALL TESTS PASSED!
+) else (
+    echo !failed_tests! TEST(S) FAILED
+)
+
+pause
+goto :eof
+
+:discover_tests
+set "test_dir=%~1"
+set "prefix=%~2"
+if exist "%test_dir%\" (
+    for %%f in ("%test_dir%\test_*.gd") do (
+        call :format_test_name "%%~nf" test_name
+        echo   %prefix%!test_name!: %%f
+    )
+)
+goto :eof
+
+:run_tests
+set "test_dir=%~1"
+set "prefix=%~2"
+if exist "%test_dir%\" (
+    for %%f in ("%test_dir%\test_*.gd") do (
+        call :format_test_name "%%~nf" test_name
+        call :run_single_test "%%f" "%prefix%!test_name!"
+    )
+)
+goto :eof
+
+:format_test_name
+set "filename=%~1"
+set "result=%filename:test_=%"
+set "%~2=%result:_= %"
+goto :eof
+
+:run_single_test
+set "test_file=%~1"
+set "test_name=%~2"
+
+echo.
+echo === %test_name% ===
+echo Running: %test_file%
+
+godot --headless --script "%test_file%"
+if !errorlevel! equ 0 (
+    echo PASSED: %test_name%
+) else (
+    echo FAILED: %test_name%
+    set /a failed_tests+=1
+)
+set /a total_tests+=1
+echo.
+goto :eof