fix unlocked flake.lock in tests

lib/clanTest/flake-module.nix

@@ -158,13 +158,25 @@ in
           '';
 
       # the test's flake.nix with locked clan-core input
-      flakeForSandbox = hostPkgs.runCommand "offline-flake-for-test-${config.name}" { } ''
+      flakeForSandbox =
+        hostPkgs.runCommand "offline-flake-for-test-${config.name}"
+          {
+            nativeBuildInputs = [ hostPkgs.nix ];
+          }
+          ''
             cp -r ${config.clan.directory} $out
             chmod +w -R $out
             substituteInPlace $out/flake.nix \
               --replace-fail \
                 "https://git.clan.lol/clan/clan-core/archive/main.tar.gz" \
                 "${clan-core.packages.${hostPkgs.system}.clan-core-flake}"
+
+            # Create a proper lock file for the test flake
+            export HOME=$(mktemp -d)
+            nix flake lock $out \
+              --extra-experimental-features 'nix-command flakes' \
+              --override-input clan-core ${clan-core.packages.${hostPkgs.system}.clan-core-flake} \
+              --override-input nixpkgs ${clan-core.inputs.nixpkgs}
           '';
     in
     {

pkgs/clan-cli/clan_cli/tests/fixtures_flakes.py

@@ -14,6 +14,7 @@ from clan_cli.tests import age_keys
 from clan_cli.tests.fixture_error import FixtureError
 from clan_cli.tests.root import CLAN_CORE
 from clan_cli.tests.temporary_dir import TEMPDIR
+from clan_lib import cmd
 from clan_lib.dirs import (
     TemplateType,
     clan_templates,
@@ -23,7 +24,7 @@ from clan_lib.dirs import (
 from clan_lib.flake import Flake
 from clan_lib.locked_open import locked_open
 from clan_lib.machines.machines import Machine
-from clan_lib.nix import nix_test_store
+from clan_lib.nix import nix_command, nix_test_store
 
 log = logging.getLogger(__name__)
 
@@ -86,6 +87,11 @@ def substitute(
     print(f"flake: {flake}")
     file.write_text(buf)
 
+    # Lock the flake after substitution if clan_core was replaced
+    if clan_core_flake:
+        flake_dir = file.parent
+        cmd.run(nix_command(["flake", "lock"]), cmd.RunOpts(cwd=flake_dir))
+
 
 class FlakeForTest(NamedTuple):
     path: Path