Add test case for filtering patterns by category

Co-authored-by: swissspidy <[email protected]>

Author: Copilot

features/pattern.feature

@@ -17,6 +17,11 @@ Feature: Manage WordPress block patterns
     [{"name":"core\/query-standard-posts","title":"Standard"}]
     """
 
+  @require-wp-5.5
+  Scenario: Filtering block patterns by category
+    When I run `wp pattern list --category=buttons --format=count`
+    Then STDOUT should match /^\d+$/
+
   @require-wp-5.5
   Scenario: Getting a specific block pattern
     When I run `wp pattern list --format=csv --fields=name`