diff --git a/Lib/test/test_unparse.py b/Lib/test/test_unparse.py
index 45d819f175bb933..3e796860cbcf22a 100644
--- a/Lib/test/test_unparse.py
+++ b/Lib/test/test_unparse.py
@@ -285,6 +285,8 @@ class DirectoryTestCase(ASTTestCase):
     lib_dir = pathlib.Path(__file__).parent / ".."
     test_directories = (lib_dir, lib_dir / "test")
     skip_files = {"test_fstring.py"}
+    run_always_files = {"test_grammar.py", "test_syntax.py", "test_compile.py",
+                        "test_ast.py", "test_asdl_parser.py"}
 
     _files_to_test = None
 
@@ -301,9 +303,17 @@ def files_to_test(cls):
             if not item.name.startswith("bad")
         ]
 
+        tests_to_run_always = {item for item in items if
+                               item.name in cls.run_always_files}
+
         # Test limited subset of files unless the 'cpu' resource is specified.
         if not test.support.is_resource_enabled("cpu"):
-            items = random.sample(items, 10)
+            items = set(random.sample(items, 10))
+
+        # Make sure that at least tests that heavily use grammar features are
+        # considered to reduce the change of missing something.
+
+        items = list(items | tests_to_run_always)
 
         # bpo-31174: Store the names sample to always test the same files.
         # It prevents false alarms when hunting reference leaks.