test: VM smoke and Lightning regtest suites

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/regtest-core.nix

@@ -0,0 +1,109 @@
+# regtest-core — NixOS-native Lightning regtest integration test.
+#
+# A reproducible, hermetic replacement for the core of the docker
+# `legend-regtest-enviroment` stack (aiolabs/omnixient#27): one VM running
+# bitcoind(regtest) + Core Lightning + LND (the bitcoin pack's nix-bitcoin
+# modules), driving a real payment flow and asserting it settles.
+#
+# Both LN nodes are co-located on one node and share the local bitcoind;
+# lnd's p2p port is moved to 9736 so it doesn't clash with clightning's
+# 9735. CLIs are run as the nix-bitcoin `operator` user, matching how
+# nix-bitcoin's own test suite drives them.
+#
+# The node config is shared with the interactive dev VM via
+# tests/regtest-node.nix so the two can never drift.
+#
+# Run headless:
+#   nix build .#checks.x86_64-linux.regtest-core -L
+# Interactive driver (poke the node by hand):
+#   nix build .#checks.x86_64-linux.regtest-core.driverInteractive
+#   ./result/bin/nixos-test-driver
+# Friendlier interactive shell (SSH, copy/paste, operator user, helpers):
+#   nix run .#regtest        (see docs/regtest.md)
+{
+  nixpkgs,
+  system ? "x86_64-linux",
+  nix-bitcoin,
+  ...
+}:
+
+let
+  pkgs = import nixpkgs {
+    inherit system;
+    config.allowUnfree = true;
+  };
+in
+pkgs.testers.runNixOSTest {
+  name = "omni-regtest-core";
+
+  nodes.regtest = {
+    imports = [
+      nix-bitcoin.nixosModules.default
+      ./regtest-node.nix # shared bitcoind + CLN + LND config
+    ];
+  };
+
+  testScript = ''
+    def op(cmd):
+        """Run a command as the nix-bitcoin operator and return stdout."""
+        return regtest.succeed(f"runuser -u operator -- {cmd}")
+
+    regtest.start()
+
+    # --- services up ---
+    regtest.wait_for_unit("bitcoind.service")
+    regtest.wait_for_unit("clightning.service")
+    regtest.wait_for_unit("lnd.service")
+
+    # CLIs answer (clightning/lnd take a moment past unit-active to be RPC-ready).
+    regtest.wait_until_succeeds("runuser -u operator -- lightning-cli getinfo", timeout=120)
+    regtest.wait_until_succeeds("runuser -u operator -- lncli getinfo", timeout=120)
+
+    # --- both LN nodes synced to the pre-mined regtest chain ---
+    regtest.wait_until_succeeds(
+        f"[[ $(runuser -u operator -- lightning-cli getinfo | jq -M .blockheight) == {110} ]]",
+        timeout=120,
+    )
+    regtest.wait_until_succeeds(
+        f"[[ $(runuser -u operator -- lncli getinfo | jq -M .block_height) == {110} ]]",
+        timeout=120,
+    )
+
+    # --- fund LND's on-chain wallet from the bitcoind test wallet ---
+    lnd_addr = op("lncli newaddress p2wkh | jq -r .address").strip()
+    op(f"bitcoin-cli -rpcwallet=test sendtoaddress {lnd_addr} 5")
+    mine_addr = op("bitcoin-cli -rpcwallet=test getnewaddress").strip()
+    op(f"bitcoin-cli -rpcwallet=test generatetoaddress 6 {mine_addr}")
+    regtest.wait_until_succeeds(
+        "[[ $(runuser -u operator -- lncli walletbalance | jq -M '.confirmed_balance | tonumber') -gt 0 ]]",
+        timeout=120,
+    )
+
+    # --- connect LND -> CLN and open a channel ---
+    cln_id = op("lightning-cli getinfo | jq -r .id").strip()
+    op(f"lncli connect {cln_id}@127.0.0.1:9735")
+    op(f"lncli openchannel --node_key={cln_id} --local_amt=1000000")  # 0.01 BTC
+
+    # confirm the channel and wait for it to go active on the LND side
+    op(f"bitcoin-cli -rpcwallet=test generatetoaddress 6 {mine_addr}")
+    regtest.wait_until_succeeds(
+        "[[ $(runuser -u operator -- lncli listchannels | jq '[.channels[] | select(.active)] | length') -ge 1 ]]",
+        timeout=240,
+    )
+
+    # --- CLN issues an invoice, LND pays it ---
+    bolt11 = op(
+        "lightning-cli invoice 100000000 regtest-core-test 'regtest-core payment' | jq -r .bolt11"
+    ).strip()  # 100000 sat = 100,000,000 msat
+    op(f"lncli payinvoice --force {bolt11}")
+
+    # --- assert CLN saw the invoice settle ---
+    regtest.wait_until_succeeds(
+        "[[ $(runuser -u operator -- lightning-cli listinvoices regtest-core-test "
+        "| jq -r '.invoices[0].status') == paid ]]",
+        timeout=180,
+    )
+
+    print("regtest-core: LND -> CLN channel opened and invoice paid ✓")
+  '';
+}