new test for GUI.

Author: Kiguli

tests/test_gui.py

@@ -0,0 +1,22 @@
+import subprocess
+import sys
+import os
+
+def test_main_runs():
+    """Check that main.py launches the GUI and exits without errors."""
+
+    main_path = os.path.join(os.path.dirname(__file__), "..", "main.py")
+    assert os.path.exists(main_path), f"main.py not found at {main_path}"
+
+    env = os.environ.copy()
+    env["PYTHONPATH"] = os.path.join(os.path.dirname(__file__), "..")
+    env["AUTO_CLOSE_GUI"] = "1"  # auto-close GUI after 1 second
+
+    result = subprocess.run(
+        [sys.executable, main_path],
+        capture_output=True,
+        text=True,
+        env=env
+    )
+
+    assert result.returncode == 0, f"main.py failed with error:\n{result.stderr}"