lnwallet: prevent static fee estimator fees from being modified

Modifying the static fees is not thread safe. In this commit the fees
are made immutable.

htlcswitch/link_test.go

@@ -1795,7 +1795,7 @@ func TestChannelLinkBandwidthConsistency(t *testing.T) {
 	coreLink.cfg.HodlMask = hodl.MaskFromFlags(hodl.ExitSettle)
 	coreLink.cfg.DebugHTLC = true
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2206,7 +2206,7 @@ func TestChannelLinkBandwidthConsistencyOverflow(t *testing.T) {
 		aliceMsgs              = coreLink.cfg.Peer.(*mockPeer).sentMsgs
 	)
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2453,7 +2453,7 @@ func TestChannelLinkTrimCircuitsPending(t *testing.T) {
 
 	// Compute the static fees that will be used to determine the
 	// correctness of Alice's bandwidth when forwarding HTLCs.
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2731,7 +2731,7 @@ func TestChannelLinkTrimCircuitsNoCommit(t *testing.T) {
 
 	// Compute the static fees that will be used to determine the
 	// correctness of Alice's bandwidth when forwarding HTLCs.
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)
@@ -2989,7 +2989,7 @@ func TestChannelLinkBandwidthChanReserve(t *testing.T) {
 		aliceMsgs              = coreLink.cfg.Peer.(*mockPeer).sentMsgs
 	)
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		t.Fatalf("unable to query fee estimator: %v", err)

htlcswitch/test_utils.go

@@ -273,7 +273,7 @@ func createTestChannel(alicePrivKey, bobPrivKey []byte,
 		return nil, nil, nil, nil, err
 	}
 
-	estimator := &lnwallet.StaticFeeEstimator{FeePerKW: 6000}
+	estimator := lnwallet.NewStaticFeeEstimator(6000, 0)
 	feePerKw, err := estimator.EstimateFeePerKW(1)
 	if err != nil {
 		return nil, nil, nil, nil, err