1 files changed, 9 insertions, 5 deletions
diff --git a/tools/testing/selftests/tc-testing/tdc_helper.py b/tools/testing/selftests/tc-testing/tdc_helper.py
index 0440d252c4c5..adb52fe3acc1 100644
--- a/tools/testing/selftests/tc-testing/tdc_helper.py
+++ b/tools/testing/selftests/tc-testing/tdc_helper.py
@@ -16,9 +16,9 @@ def get_categorized_testlist(alltests, ucat):
 
 
 def get_unique_item(lst):
-    """ For a list, return a list of the unique items in the list. """
+    """Return unique items while preserving original order."""
     if len(lst) > 1:
-        return list(set(lst))
+        return list(dict.fromkeys(lst))
     else:
         return lst
 
@@ -38,10 +38,14 @@ def list_test_cases(testlist):
 
 
 def list_categories(testlist):
-    """ Show all categories that are present in a test case file. """
-    categories = set(map(lambda x: x['category'], testlist))
+    """Show all unique categories present in the test cases."""
+    categories = set()
+    for t in testlist:
+        if 'category' in t:
+            categories.update(t['category'])
+
     print("Available categories:")
-    print(", ".join(str(s) for s in categories))
+    print(", ".join(sorted(categories)))
     print("")