Issue #11798: fix tests for regrtest -R :
diff --git a/Lib/unittest/suite.py b/Lib/unittest/suite.py
index 176af57..ca82765 100644
--- a/Lib/unittest/suite.py
+++ b/Lib/unittest/suite.py
@@ -16,6 +16,8 @@
 class BaseTestSuite(object):
     """A simple test suite that doesn't provide class or module shared fixtures.
     """
+    _cleanup = True
+
     def __init__(self, tests=()):
         self._tests = []
         self.addTests(tests)
@@ -61,7 +63,8 @@
             if result.shouldStop:
                 break
             test(result)
-            self._removeTestAtIndex(index)
+            if self._cleanup:
+                self._removeTestAtIndex(index)
         return result
 
     def _removeTestAtIndex(self, index):
@@ -115,7 +118,8 @@
             else:
                 test.debug()
 
-            self._removeTestAtIndex(index)
+            if self._cleanup:
+                self._removeTestAtIndex(index)
 
         if topLevel:
             self._tearDownPreviousClass(None, result)