diff --git a/modules/perc-packages/src/test/java/com/percussion/packages/PSPackageBuilderTest.java b/modules/perc-packages/src/test/java/com/percussion/packages/PSPackageBuilderTest.java
index 71d9c6e56d..6f329866ea 100644
--- a/modules/perc-packages/src/test/java/com/percussion/packages/PSPackageBuilderTest.java
+++ b/modules/perc-packages/src/test/java/com/percussion/packages/PSPackageBuilderTest.java
@@ -147,7 +147,8 @@ private boolean isChangeableFile(String entryName) {
         || lower.endsWith(".htm")
         || lower.endsWith(".css")
         || lower.endsWith(".txt")
-        || lower.endsWith(".md");
+        || lower.endsWith(".md")
+        || lower.endsWith(".extension");
   }
 
   /** Reads all entries (files and directories) from a zip file into a name-to-content map. */