Add tests for move_relative command parameter parsing

Verify the underscore-delimited parameter format handles both the
original pan+tilt format and the new pan+tilt+zoom format correctly.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frigate/test/test_ptz_commands.py

@@ -0,0 +1,40 @@
+from unittest import TestCase, main
+
+
+class TestMoveRelativeParsing(TestCase):
+    """Test the move_relative command parameter parsing logic."""
+
+    def _parse_move_relative(self, param: str):
+        """Replicate the parsing logic from OnvifController.handle_command_async."""
+        parts = param.split("_")
+        _, pan, tilt = parts[0], parts[1], parts[2]
+        zoom = float(parts[3]) if len(parts) > 3 else 0
+        return float(pan), float(tilt), zoom
+
+    def test_pan_tilt_only(self):
+        pan, tilt, zoom = self._parse_move_relative("move_0.5_-0.3")
+        self.assertAlmostEqual(pan, 0.5)
+        self.assertAlmostEqual(tilt, -0.3)
+        self.assertAlmostEqual(zoom, 0)
+
+    def test_pan_tilt_with_zoom(self):
+        pan, tilt, zoom = self._parse_move_relative("move_0.5_-0.3_0.8")
+        self.assertAlmostEqual(pan, 0.5)
+        self.assertAlmostEqual(tilt, -0.3)
+        self.assertAlmostEqual(zoom, 0.8)
+
+    def test_zero_zoom(self):
+        pan, tilt, zoom = self._parse_move_relative("move_0.0_0.0_0.0")
+        self.assertAlmostEqual(pan, 0.0)
+        self.assertAlmostEqual(tilt, 0.0)
+        self.assertAlmostEqual(zoom, 0.0)
+
+    def test_negative_values(self):
+        pan, tilt, zoom = self._parse_move_relative("move_-1.0_-1.0_0.5")
+        self.assertAlmostEqual(pan, -1.0)
+        self.assertAlmostEqual(tilt, -1.0)
+        self.assertAlmostEqual(zoom, 0.5)
+
+
+if __name__ == "__main__":
+    main(verbosity=2)