fix idempotency gne port uctoff

backend/tests/test_drop_registers_matching_last_verified.py

@@ -21,9 +21,17 @@ def test_drop_registers_keeps_reg178_when_mask_differs():
     assert skipped == []
 
 
-def test_drop_registers_skips_reg179_when_mask_matches():
-    registers = [(179, "control_board_special_1", 2)]  # bits0–1 = 2 (cutoff ON)
-    last_verified = {179: 0x1236}  # ...0110b => bits0–1 still == 2
+def test_drop_registers_keeps_reg179_when_mask_matches_but_not_clean():
+    registers = [(179, "control_board_special_1", 2)]  # want cutoff ON (clean value)
+    last_verified = {179: 0x1236}  # bits0–1 still == 2, but not a clean 2/3 value
+    out, skipped = _drop_registers_matching_last_verified(registers, last_verified)
+    assert out == registers
+    assert skipped == []
+
+
+def test_drop_registers_skips_reg179_when_clean_value_matches():
+    registers = [(179, "control_board_special_1", 2)]  # want cutoff ON (clean value)
+    last_verified = {179: 2}  # already clean cutoff ON
     out, skipped = _drop_registers_matching_last_verified(registers, last_verified)
     assert out == []
     assert skipped == [179]