diff --git a/mmengine/testing/_internal/distributed.py b/mmengine/testing/_internal/distributed.py
index b795cc9456..2e1d8952e5 100644
--- a/mmengine/testing/_internal/distributed.py
+++ b/mmengine/testing/_internal/distributed.py
@@ -88,16 +88,15 @@ def wrapper(self):
 
         return types.MethodType(wrapper, self)
 
-    # The main process spawns N subprocesses that run the test.
-    # Constructor patches current instance test method to
-    # assume the role of the main process and join its subprocesses,
-    # or run the underlying test function.
-    def __init__(self, method_name: str = 'runTest') -> None:
-        super().__init__(method_name)
+    def setUp(self) -> None:
+        # The main process spawns N subprocesses that run the test.
+        # This patches current instance test method to
+        # assume the role of the main process and join its subprocesses,
+        # or run the underlying test function.
+        method_name = self._testMethodName
         fn = getattr(self, method_name)
         setattr(self, method_name, self.join_or_run(fn))
 
-    def setUp(self) -> None:
         super().setUp()
         self.skip_return_code_checks = []  # type: ignore[var-annotated]
         self.processes = []  # type: ignore[var-annotated]