Add test script to contrib folder

[rustaceanrob]

Completing each step to run the integration tests isn't great, and all that is needed is a path to the bitcoin core source code, so this adds a shell script to build and run everything in a single script.

[xyzconstant]

tACK 4992ba0

Tested in macOS and Ubuntu. LGTM, left one inline nit.

Also, I think a good addition would be a datadir env config, so it doesn't mess with the default datadir and always runs over a fresh setup.

I have this diff locally with that datadir option, and it works, also the fallback datadir path is unaffected:

diff --git a/contrib/run-tests.sh b/contrib/run-tests.sh
index 4e7c4a9..1076a5d 100755
--- a/contrib/run-tests.sh
+++ b/contrib/run-tests.sh
@@ -15,6 +15,7 @@ fi
 BITCOIN_SRC=$(cd "$1" && pwd)
 REPO_ROOT=$(cd "$(dirname "$0")/.." && pwd)
 BITCOIN_BIN="$BITCOIN_SRC/build/bin/bitcoin"
+TEMP_DATADIR=/tmp/capnp-types-tests
 
 echo "==> Building Bitcoin Core in $BITCOIN_SRC"
 (
@@ -26,17 +27,19 @@ echo "==> Building Bitcoin Core in $BITCOIN_SRC"
 stop_bitcoin() {
     if [ -n "${BITCOIN_STARTED:-}" ]; then
         echo "==> Stopping bitcoin"
-        "$BITCOIN_BIN" rpc -chain=regtest stop || true
+        "$BITCOIN_BIN" rpc -chain=regtest -datadir="$TEMP_DATADIR" stop || true
     fi
 }
 trap stop_bitcoin EXIT
 
 echo "==> Starting bitcoin node (regtest, IPC)"
-"$BITCOIN_BIN" node -chain=regtest -ipcbind=unix -server -debug=ipc -daemon
+rm -rf "$TEMP_DATADIR"
+mkdir -p "$TEMP_DATADIR"
+"$BITCOIN_BIN" node -chain=regtest -ipcbind=unix -server -debug=ipc -datadir="$TEMP_DATADIR" -daemon
 BITCOIN_STARTED=1
 
 echo "==> Running cargo test"
 (
     cd "$REPO_ROOT"
-    BITCOIN_BIN="$BITCOIN_BIN" cargo test
+    BITCOIN_BIN="$BITCOIN_BIN" BITCOIN_DATADIR="$TEMP_DATADIR" cargo test
 )
diff --git a/tests/util/bitcoin_core.rs b/tests/util/bitcoin_core.rs
index b830e16..1efebab 100644
--- a/tests/util/bitcoin_core.rs
+++ b/tests/util/bitcoin_core.rs
@@ -5,7 +5,8 @@ use std::{
 };
 
 use crate::util::bitcoin_core_wallet::{
-    bitcoin_rpc_json, bitcoin_test_wallet, ensure_wallet_loaded, mine_blocks_to_new_address,
+    bitcoin_datadir, bitcoin_rpc_json, bitcoin_test_wallet, ensure_wallet_loaded,
+    mine_blocks_to_new_address,
 };
 use bitcoin_capnp_types::{
     init_capnp::init,
@@ -23,15 +24,20 @@ use tokio_util::compat::{Compat, TokioAsyncReadCompatExt, TokioAsyncWriteCompatE
 static CHAIN_SETUP: Once = Once::new();
 
 pub fn unix_socket_path() -> PathBuf {
-    let home_dir_string = std::env::var("HOME").unwrap();
-    let home_dir = home_dir_string.parse::<PathBuf>().unwrap();
-    let bitcoin_dir = if cfg!(target_os = "macos") {
-        home_dir
-            .join("Library")
-            .join("Application Support")
-            .join("Bitcoin")
-    } else {
-        home_dir.join(".bitcoin")
+    let bitcoin_dir = match bitcoin_datadir() {
+        Some(datadir) => datadir.parse::<PathBuf>().unwrap(),
+        None => {
+            let home_dir_string = std::env::var("HOME").unwrap();
+            let home_dir = home_dir_string.parse::<PathBuf>().unwrap();
+            if cfg!(target_os = "macos") {
+                home_dir
+                    .join("Library")
+                    .join("Application Support")
+                    .join("Bitcoin")
+            } else {
+                home_dir.join(".bitcoin")
+            }
+        }
     };
     let regtest_dir = bitcoin_dir.join("regtest");
     regtest_dir.join("node.sock")
diff --git a/tests/util/bitcoin_core_wallet.rs b/tests/util/bitcoin_core_wallet.rs
index 9c37fdf..e8fb4db 100644
--- a/tests/util/bitcoin_core_wallet.rs
+++ b/tests/util/bitcoin_core_wallet.rs
@@ -9,6 +9,10 @@ fn bitcoin_bin() -> String {
     std::env::var("BITCOIN_BIN").unwrap_or_else(|_| "bitcoin".to_owned())
 }
 
+pub fn bitcoin_datadir() -> Option<String> {
+    std::env::var("BITCOIN_DATADIR").ok()
+}
+
 fn bitcoin_rpc(wallet: Option<&str>, args: &[&str]) -> Result<String, String> {
     let owned_args: Vec<String> = args.iter().map(|arg| (*arg).to_owned()).collect();
     bitcoin_rpc_owned(wallet, &owned_args)
@@ -29,6 +33,9 @@ pub fn bitcoin_test_wallet() -> String {
 fn bitcoin_rpc_owned(wallet: Option<&str>, args: &[String]) -> Result<String, String> {
     let mut command = Command::new(bitcoin_bin());
     command.arg("rpc").arg("-chain=regtest").arg("-rpcwait");
+    if let Some(datadir) = bitcoin_datadir() {
+        command.arg(format!("-datadir={datadir}"));
+    }
     if let Some(wallet) = wallet {
         command.arg(format!("-rpcwallet={wallet}"));
     }

Overall, I think this script is fine since it simplifies the development workflow.

[xyzconstant]

Suggested change

	# Usage: contrib/run-integration-tests.sh <path-to-bitcoin-source>
	# Usage: contrib/run-tests.sh <path-to-bitcoin-source>