From 69eafc8c4e1eae6aa06585ab0e72ebf9c81c56ef Mon Sep 17 00:00:00 2001
From: ffranr <ffranr@proton.me>
Date: Mon, 6 Jan 2025 11:37:27 +0000
Subject: [PATCH] itest: add harness for invoking chantools binary

Add a test harness to execute the chantools binary via the command line
and parse its output.
---
 itest/chantools_harness.go | 160 +++++++++++++++++++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 itest/chantools_harness.go

diff --git a/itest/chantools_harness.go b/itest/chantools_harness.go
new file mode 100644
index 000000000..139ae6e34
--- /dev/null
+++ b/itest/chantools_harness.go
@@ -0,0 +1,160 @@
+package itest
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/btcsuite/btcd/btcutil/psbt"
+	"github.com/stretchr/testify/require"
+)
+
+// chantoolsCmdBuilder is a helper function that creates a new exec.Cmd instance
+// for the chantools binary.
+func chantoolsCmdBuilder(binPath string, workingDir string,
+	args ...string) exec.Cmd {
+
+	cmd := exec.Command(binPath, args...)
+
+	// Set the working directory so that any log files are handled
+	// gracefully.
+	cmd.Dir = workingDir
+
+	// Set the wallet password.
+	cmd.Env = append(os.Environ(), "WALLET_PASSWORD=-")
+
+	// Set the seed generation passphrase.
+	cmd.Env = append(cmd.Env, "AEZEED_PASSPHRASE=-")
+
+	return *cmd
+}
+
+// ChantoolsHarness is a helper struct that provides a way to interact with
+// the chantools binary.
+type ChantoolsHarness struct {
+	// path is the path to the chantools binary.
+	path string
+
+	// workingDir is the chantools harness working directory.
+	workingDir string
+
+	// walletDbPath is the path to the wallet.db file created by chantools.
+	walletDbPath string
+}
+
+// NewChantoolsHarness creates a new instance of the ChantoolsHarness struct.
+func NewChantoolsHarness(t *testing.T) ChantoolsHarness {
+	path, err := exec.LookPath("chantools")
+	require.NoError(t, err, "chantools is not installed or not in PATH")
+
+	t.Logf("Using chantools binary at: %v", path)
+
+	// Create a temporary directory to store the log file and wallet.db
+	// file.
+	workingDir, err := os.MkdirTemp("", "itest-tapd-chantools")
+	require.NoError(t, err, "failed to create chantools working directory")
+
+	// Assert that the version of chantools is as expected.
+	cmd := chantoolsCmdBuilder(path, workingDir, "--version")
+	versionOut, err := cmd.CombinedOutput()
+	require.NoError(t, err, "failed to get chantools version")
+
+	versionOutStr := string(versionOut)
+	if !strings.Contains(versionOutStr, "chantools version v0.13.5") {
+		t.Fatalf("unexpected chantools version: %v", versionOutStr)
+	}
+
+	return ChantoolsHarness{
+		path:         path,
+		workingDir:   workingDir,
+		walletDbPath: filepath.Join(workingDir, "wallet.db"),
+	}
+}
+
+// buildCmd is a helper method that creates a new exec.Cmd instance for the
+// chantools binary.
+func (c *ChantoolsHarness) buildCmd(args ...string) exec.Cmd {
+	return chantoolsCmdBuilder(c.path, c.workingDir, args...)
+}
+
+// CreateWallet creates a new wallet using the chantools binary.
+func (c *ChantoolsHarness) CreateWallet(t *testing.T) {
+	cmd := c.buildCmd(
+		"--regtest", "createwallet", "--bip39",
+		"--generateseed", "--walletdbdir", c.workingDir,
+	)
+
+	cmdOut, err := cmd.CombinedOutput()
+	require.NoError(t, err)
+
+	t.Logf("Chantools createwallet output: %v", string(cmdOut))
+}
+
+// DeriveKey derives a new key using the chantools binary.
+func (c *ChantoolsHarness) DeriveKey(t *testing.T) (string, string) {
+	cmd := c.buildCmd(
+		"--regtest", "derivekey", "--walletdb", c.walletDbPath,
+		"--path", "m/86'/1'/0'", "--neuter",
+	)
+
+	cmdOut, err := cmd.CombinedOutput()
+	require.NoError(t, err)
+
+	cmdOutStr := string(cmdOut)
+	t.Logf("Chantools derivekey output: %v", cmdOutStr)
+
+	// Parsing for xpub.
+	xpubPattern := `Extended public key \(xpub\):\s+([a-zA-Z0-9]+)`
+	xpubRegex := regexp.MustCompile(xpubPattern)
+	matches := xpubRegex.FindStringSubmatch(cmdOutStr)
+	require.Len(t, matches, 2)
+
+	xpub := matches[1]
+	require.NotEmpty(t, xpub)
+
+	// Parsing for master fingerprint.
+	fingerprintPattern := `Master Fingerprint:\s+([a-f0-9]+)`
+	fingerprintRegex := regexp.MustCompile(fingerprintPattern)
+	matches = fingerprintRegex.FindStringSubmatch(cmdOutStr)
+	require.Len(t, matches, 2)
+
+	masterFingerprint := matches[1]
+	require.Len(t, masterFingerprint, 8)
+
+	return xpub, masterFingerprint
+}
+
+// SignPsbt signs a PSBT using the chantools binary.
+func (c *ChantoolsHarness) SignPsbt(t *testing.T, psbtStr string) psbt.Packet {
+	cmd := c.buildCmd(
+		"--regtest", "signpsbt", "--walletdb", c.walletDbPath,
+		"--psbt", psbtStr,
+	)
+
+	cmdOut, err := cmd.CombinedOutput()
+	require.NoError(t, err)
+
+	cmdOutStr := string(cmdOut)
+	t.Logf("Chantools signpsbt output: %v", cmdOutStr)
+
+	// Extract the signed PSBT.
+	psbtPattern := `Successfully signed PSBT:\n\n([a-zA-Z0-9+/=]+)`
+	psbtRegex := regexp.MustCompile(psbtPattern)
+	matches := psbtRegex.FindStringSubmatch(cmdOutStr)
+	require.Len(t, matches, 2)
+
+	signedPsbtStr := matches[1]
+	require.NotEmpty(t, signedPsbtStr)
+
+	// Parse the signed PSBT.
+	signedPsbt, err := psbt.NewFromRawBytes(bytes.NewReader(
+		[]byte(signedPsbtStr)), true,
+	)
+	require.NoError(t, err)
+
+	return *signedPsbt
+}