diff --git a/test/test-80-compression-node-opcua/main.js b/test/test-80-compression-node-opcua/main.js
index 304beea70..7d2d7f1ae 100644
--- a/test/test-80-compression-node-opcua/main.js
+++ b/test/test-80-compression-node-opcua/main.js
@@ -6,6 +6,10 @@
  * A test with a large number of modules with symlinks
  * (installed with npm) and compress
  *
+ * node-opcua is pinned to 2.181.0 in package.json: 2.184.0 made the packages
+ * ESM ("type": "module", import.meta.dirname), which esbuild's CJS bundle
+ * resolves to undefined — node-opcua-nodesets then calls path.join(undefined).
+ * Unpin only together with an esbuild config that emits ESM.
  */
 
 const fs = require('fs');
diff --git a/test/test-80-compression-node-opcua/package.json b/test/test-80-compression-node-opcua/package.json
index 6a60ac5fb..463968bb4 100644
--- a/test/test-80-compression-node-opcua/package.json
+++ b/test/test-80-compression-node-opcua/package.json
@@ -12,9 +12,9 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
-    "node-opcua-address-space": "^2.36.0",
+    "node-opcua-address-space": "2.181.0",
     "node-opcua-crypto": "^1.7.1",
-    "node-opcua-nodesets": "^2.36.0"
+    "node-opcua-nodesets": "2.181.0"
   },
   "devDependencies": {
     "esbuild": "^0.20.0"