Add reproducible Radxa AirPlay and Bluetooth mixer setup

tests/test_backup.py

@@ -0,0 +1,46 @@
+import importlib.util
+import json
+from pathlib import Path
+import subprocess
+import tempfile
+import unittest
+from unittest.mock import patch
+
+spec=importlib.util.spec_from_file_location('backup',Path(__file__).parents[1]/'scripts/backup.py')
+b=importlib.util.module_from_spec(spec); spec.loader.exec_module(b)
+
+
+class BackupTests(unittest.TestCase):
+    def test_restores_original_file_and_removes_new_file(self):
+        with tempfile.TemporaryDirectory() as d:
+            base=Path(d); original=base/'old.conf'; new=base/'new.conf'
+            original.write_text('original')
+            def ctl(*args): return subprocess.CompletedProcess(args, 1, stdout='')
+            with patch.object(b,'PATHS',[str(original),str(new)]), patch.object(b,'ctl',side_effect=ctl):
+                b.snapshot(base/'backup')
+                original.write_text('changed'); new.write_text('new')
+                b.restore(base/'backup')
+            self.assertEqual(original.read_text(),'original')
+            self.assertFalse(new.exists())
+
+    def test_preserves_symlinks(self):
+        with tempfile.TemporaryDirectory() as d:
+            base=Path(d); link=base/'service'; original=base/'target'
+            original.write_text('original'); link.symlink_to(original)
+            def ctl(*args): return subprocess.CompletedProcess(args, 1, stdout='')
+            with patch.object(b,'PATHS',[str(link)]), patch.object(b,'ctl',side_effect=ctl):
+                b.snapshot(base/'backup')
+                link.unlink(); link.write_text('replaced')
+                b.restore(base/'backup')
+            self.assertTrue(link.is_symlink())
+            self.assertEqual(link.read_text(),'original')
+
+    def test_rejects_snapshot_with_unexpected_file(self):
+        with tempfile.TemporaryDirectory() as d:
+            base=Path(d)
+            (base/'manifest.json').write_text(json.dumps({'files':{'/unexpected':True},'units':{}}))
+            with patch.object(b,'ctl') as ctl, self.assertRaises(ValueError): b.restore(base)
+            ctl.assert_not_called()
+
+
+if __name__=='__main__': unittest.main()