diff --git a/tests/wplua/meson.build b/tests/wplua/meson.build
index fc05ed1d..47453544 100644
--- a/tests/wplua/meson.build
+++ b/tests/wplua/meson.build
@@ -2,6 +2,7 @@ common_deps = [wplua_dep, pipewire_dep, wp_dep]
 common_env = [
   'G_TEST_SRCDIR=@0@'.format(meson.current_source_dir()),
   'G_TEST_BUILDDIR=@0@'.format(meson.current_build_dir()),
+  'WIREPLUMBER_CONFIG_DIR=/invalid',
   'WIREPLUMBER_DATA_DIR=@0@'.format(meson.current_source_dir()),
   'WIREPLUMBER_MODULE_DIR=@0@'.format(meson.current_build_dir() / '..' / '..' / 'modules'),
   'WIREPLUMBER_DEBUG=7',