diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index 974ebd4..d2799c3 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -905,6 +905,8 @@
         self.assertEquals(encoder("a")[1], 1)
         self.assertEquals(encoder("\xe9\u0142")[1], 2)
 
+        self.assertEquals(codecs.escape_encode(br'\x00')[1], 4)
+
 # From http://www.gnu.org/software/libidn/draft-josefsson-idn-test-vectors.html
 nameprep_tests = [
     # 3.1 Map to nothing.