sweep: make sure max fee rate can be reached

Previously we don't allow confTarget to be 0, which ended up the final
position being never reached. We fix it here by allowing confTarget to
be 0 in case the deadline has already been passed for a given input.

sweep/fee_bumper_test.go

@@ -189,9 +189,9 @@ func TestCalcCurrentConfTarget(t *testing.T) {
 	require.EqualValues(t, 100, conf)
 
 	// When the current block height is 200 and deadline height is 100, the
-	// conf target should be 1 since the deadline has passed.
+	// conf target should be 0 since the deadline has passed.
 	conf = calcCurrentConfTarget(int32(200), int32(100))
-	require.EqualValues(t, 1, conf)
+	require.EqualValues(t, 0, conf)
 }
 
 // TestInitializeFeeFunction tests the initialization of the fee function.
@@ -218,7 +218,8 @@ func TestInitializeFeeFunction(t *testing.T) {
 		DeliveryAddress: changePkScript,
 		Inputs:          []input.Input{&inp},
 		Budget:          btcutil.Amount(1000),
-		MaxFeeRate:      feerate,
+		MaxFeeRate:      feerate * 10,
+		DeadlineHeight:  10,
 	}
 
 	// Mock the fee estimator to return an error.
@@ -889,7 +890,8 @@ func TestBroadcastSuccess(t *testing.T) {
 		DeliveryAddress: changePkScript,
 		Inputs:          []input.Input{&inp},
 		Budget:          btcutil.Amount(1000),
-		MaxFeeRate:      feerate,
+		MaxFeeRate:      feerate * 10,
+		DeadlineHeight:  10,
 	}
 
 	// Send the req and expect no error.
@@ -930,7 +932,8 @@ func TestBroadcastFail(t *testing.T) {
 		DeliveryAddress: changePkScript,
 		Inputs:          []input.Input{&inp},
 		Budget:          btcutil.Amount(1000),
-		MaxFeeRate:      feerate,
+		MaxFeeRate:      feerate * 10,
+		DeadlineHeight:  10,
 	}
 
 	// Mock the fee estimator to return the testing fee rate.