sweep: add test to make sure fee estimation is correct

sweep/txgenerator_test.go

@@ -0,0 +1,49 @@
+package sweep
+
+import (
+	"testing"
+
+	"github.com/btcsuite/btcd/wire"
+	"github.com/lightningnetwork/lnd/input"
+)
+
+var (
+	witnessTypes = []input.WitnessType{
+		input.CommitmentTimeLock,
+		input.HtlcAcceptedSuccessSecondLevel,
+		input.HtlcOfferedRemoteTimeout,
+		input.WitnessKeyHash,
+	}
+	expectedWeight = int64(1459)
+	expectedCsv    = 2
+	expectedCltv   = 1
+)
+
+// TestWeightEstimate tests that the estimated weight and number of CSVs/CLTVs
+// used is correct for a transaction that uses inputs with the witness types
+// defined in witnessTypes.
+func TestWeightEstimate(t *testing.T) {
+	t.Parallel()
+
+	var inputs []input.Input
+	for _, witnessType := range witnessTypes {
+		inputs = append(inputs, input.NewBaseInput(
+			&wire.OutPoint{}, witnessType,
+			&input.SignDescriptor{}, 0,
+		))
+	}
+
+	_, weight, csv, cltv := getWeightEstimate(inputs)
+	if weight != expectedWeight {
+		t.Fatalf("unexpected weight. expected %d but got %d.",
+			expectedWeight, weight)
+	}
+	if csv != expectedCsv {
+		t.Fatalf("unexpected csv count. expected %d but got %d.",
+			expectedCsv, csv)
+	}
+	if cltv != expectedCltv {
+		t.Fatalf("unexpected cltv count. expected %d but got %d.",
+			expectedCltv, cltv)
+	}
+}