diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -381,9 +381,11 @@
                 huntrleaks[1] = int(huntrleaks[1])
             if len(huntrleaks) == 2 or not huntrleaks[2]:
                 huntrleaks[2:] = ["reflog.txt"]
-            # Avoid false positives due to the character cache in
-            # stringobject.c filling slowly with random data
+            # Avoid false positives due to various caches
+            # filling slowly with random data:
             warm_char_cache()
+            warm_unicode_cache()
+            warm_int_cache()
         elif o in ('-M', '--memlimit'):
             support.set_memlimit(a)
         elif o in ('-u', '--use'):
@@ -1435,6 +1437,12 @@
     for i in range(256):
         s[i:i+1]
 
+def warm_unicode_cache():
+    x = [chr(i) for i in range(256)]
+
+def warm_int_cache():
+    x = list(range(-5, 257))
+
 def findtestdir(path=None):
     return path or os.path.dirname(__file__) or os.curdir