tapscript: add test for NewFundingScriptTree

This commit adds a test to ensure that `NewFundingScriptTree` returns
the value we expect.

Author: gijswijs

tapscript/script_test.go

@@ -0,0 +1,28 @@
+package tapscript
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestNewFundingScriptTree tests the NewFundingScriptTree function. We use this
+// function to filter out assets used for custom channel funding from the
+// balance queries. Therefor the script key cannot change since this would lead
+// to inconsistencies in the balance queries.
+func TestNewFundingScriptTree(t *testing.T) {
+	// This key, threaded through asset.NewScriptKey() would start with 02.
+	// We don't do that here so we compare it to the expected compressed
+	// form of the public key.
+	expectedTaprootKeyHex := "0350aaeb166f4234650d84a2d8a130987aeaf695020" +
+		"6e0905401ee74ff3f8d18e6"
+	expectedTaprootKeyBytes, err := hex.DecodeString(expectedTaprootKeyHex)
+	require.NoError(t, err)
+
+	fundingScriptTree := NewFundingScriptTree()
+	taprootKey := fundingScriptTree.TaprootKey
+
+	serializedTaprootKey := taprootKey.SerializeCompressed()
+	require.Equal(t, expectedTaprootKeyBytes, serializedTaprootKey)
+}