diff --git a/py/misc/cache.py b/py/misc/cache.py
index 51e345d52..12970e6d7 100644
--- a/py/misc/cache.py
+++ b/py/misc/cache.py
@@ -107,9 +107,6 @@ class BuildcostAccessCache(BasicCache):
     # time function to use for measuring build-times
     _time = gettime
 
-    def __init__(self, maxentries=64):
-        super(BuildcostAccessCache, self).__init__(maxentries)
-
     def build(self, key, builder, *args, **kwargs):
         start = self._time()
         val = builder(*args, **kwargs)
diff --git a/py/misc/testing/test_cache.py b/py/misc/testing/test_cache.py
index c4c8f5df2..be4e3406b 100644
--- a/py/misc/testing/test_cache.py
+++ b/py/misc/testing/test_cache.py
@@ -27,6 +27,12 @@ class TestBuildcostAccess(BasicCacheAPITest):
 
     def test_cache_works_somewhat_simple(self):
         cache = BuildcostAccessCache()
+        # the default ._time() call used by
+        # BuildcostAccessCache.build can 
+        # result into time()-time() == 0 which makes the below
+        # test fail randomly.  Let's rather use incrementing
+        # numbers instead. 
+        cache._time = py.std.itertools.count().next
         for x in range(cache.maxentries):
             y = cache.getorbuild(x, lambda: x)
             assert x == y