feat(plugin): add Python backend skeleton with settings management

plugins/decky-vault/tests/test_settings.py

@@ -0,0 +1,49 @@
+"""Tests for settings persistence in the Python backend."""
+import json
+import os
+import sys
+import tempfile
+import pytest
+
+# We test the settings logic directly, not through the Plugin class,
+# so we can run tests without the decky module.
+
+def write_settings(settings_path, settings):
+    """Write settings JSON to the given path."""
+    os.makedirs(os.path.dirname(settings_path), exist_ok=True)
+    with open(settings_path, 'w') as f:
+        json.dump(settings, f, indent=2)
+
+def read_settings(settings_path):
+    """Read settings JSON from the given path, return empty dict if missing."""
+    if os.path.exists(settings_path):
+        with open(settings_path, 'r') as f:
+            return json.load(f)
+    return {}
+
+def test_read_settings_returns_empty_when_file_missing():
+    with tempfile.TemporaryDirectory() as tmpdir:
+        path = os.path.join(tmpdir, "settings.json")
+        assert read_settings(path) == {}
+
+def test_write_then_read_settings():
+    with tempfile.TemporaryDirectory() as tmpdir:
+        path = os.path.join(tmpdir, "subdir", "settings.json")
+        write_settings(path, {"apiKey": "dv_test123", "exportPath": "/home/deck/Downloads"})
+        result = read_settings(path)
+        assert result["apiKey"] == "dv_test123"
+        assert result["exportPath"] == "/home/deck/Downloads"
+
+def test_write_settings_creates_directory():
+    with tempfile.TemporaryDirectory() as tmpdir:
+        path = os.path.join(tmpdir, "newdir", "settings.json")
+        write_settings(path, {"key": "value"})
+        assert os.path.exists(path)
+
+def test_read_settings_handles_corrupt_json():
+    with tempfile.TemporaryDirectory() as tmpdir:
+        path = os.path.join(tmpdir, "settings.json")
+        with open(path, 'w') as f:
+            f.write("{invalid json")
+        with pytest.raises(json.JSONDecodeError):
+            read_settings(path)