adjust exception handling for new exception; added clear messages

Author: aguilita1

.github/workflows/ci.yml

@@ -96,8 +96,8 @@ jobs:
             echo "✅ All positive tests passed."
             echo "✅ All positive tests passed." >> $GITHUB_STEP_SUMMARY
           else
-            echo "❌ One or more positive tests failed."
-            echo "❌ One or more positive tests failed." >> $GITHUB_STEP_SUMMARY
+            echo "❌ One or more positive tests failed or did not run."
+            echo "❌ One or more positive tests failed or did not run." >> $GITHUB_STEP_SUMMARY
             exit 1
           fi
 

action.yml

@@ -149,7 +149,7 @@ runs:
             console.error(`❌ Error processing ${{ inputs.label }} results:`, error);
 
             // Detect when user forgot to return a value (causing body = undefined)
-            if (error.code === 'ERR_INVALID_ARG_TYPE' && /The "data" argument must be of type string/i.test(error.message)) {
+            if (error instanceof TypeError && /Returned value from user script must be a string/i.test(error.message)) {
               console.error(`💡 Hint: Your script returned a non-string value (e.g., object, array, or undefined) — or nothing at all.\n`
                           + `Please return a string, or serialize your result using JSON.stringify.\n\n`
                           + `For example:\n\n`