diff --git a/tests/test-parseindex b/tests/test-parseindex
new file mode 100755
--- /dev/null
+++ b/tests/test-parseindex
@@ -0,0 +1,52 @@
+#!/bin/sh
+#
+# revlog.parseindex must be able to parse the index file even if
+# an index entry is split between two 64k blocks.  The ideal test
+# would be to create an index file with inline data where
+# 64k < size < 64k + 64 (64k is the size of the read buffer, 64 is
+# the size of an index entry) and with an index entry starting right
+# before the 64k block boundary, and try to read it.
+#
+# We approximate that by reducing the read buffer to 1 byte.
+#
+
+hg init a
+cd a
+echo abc > foo
+hg add foo
+hg commit -m 'add foo' -d '1000000 0'
+
+echo >> foo
+hg commit -m 'change foo' -d '1000001 0'
+hg log -r 0:
+
+cat >> test.py << EOF
+from mercurial import changelog, util
+from mercurial.node import *
+
+class singlebyteread(object):
+    def __init__(self, real):
+        self.real = real
+
+    def read(self, size=-1):
+        if size == 65536:
+            size = 1
+        return self.real.read(size)
+
+    def __getattr__(self, key):
+        return getattr(self.real, key)
+
+def opener(*args):
+    o = util.opener(*args)
+    def wrapper(*a):
+        f = o(*a)
+        return singlebyteread(f)
+    return wrapper
+
+cl = changelog.changelog(opener('.hg'))
+print cl.count(), 'revisions:'
+for r in xrange(cl.count()):
+    print short(cl.node(r))
+EOF
+
+python test.py