diff --git a/django/test/runner.py b/django/test/runner.py
index aba4fc2b39..46c8c5842d 100644
--- a/django/test/runner.py
+++ b/django/test/runner.py
@@ -800,18 +800,20 @@ def partition_suite_by_case(suite):
     ]
 
 
+def test_match_tags(test, tags, exclude_tags):
+    test_tags = set(getattr(test, 'tags', []))
+    test_fn_name = getattr(test, '_testMethodName', str(test))
+    if hasattr(test, test_fn_name):
+        test_fn = getattr(test, test_fn_name)
+        test_fn_tags = list(getattr(test_fn, 'tags', []))
+        test_tags = test_tags.union(test_fn_tags)
+    matched_tags = test_tags.intersection(tags)
+    return (matched_tags or not tags) and not test_tags.intersection(exclude_tags)
+
+
 def filter_tests_by_tags(suite, tags, exclude_tags):
     suite_class = type(suite)
-    filtered_suite = suite_class()
-
-    for test in iter_test_cases(suite):
-        test_tags = set(getattr(test, 'tags', set()))
-        test_fn_name = getattr(test, '_testMethodName', str(test))
-        test_fn = getattr(test, test_fn_name, test)
-        test_fn_tags = set(getattr(test_fn, 'tags', set()))
-        all_tags = test_tags.union(test_fn_tags)
-        matched_tags = all_tags.intersection(tags)
-        if (matched_tags or not tags) and not all_tags.intersection(exclude_tags):
-            filtered_suite.addTest(test)
-
-    return filtered_suite
+    return suite_class(
+        test for test in iter_test_cases(suite)
+        if test_match_tags(test, tags, exclude_tags)
+    )