--- a/src/calibre/test_build.py
+++ b/src/calibre/test_build.py
@@ -82,9 +82,8 @@
         del CHMFile, chmlib

     def test_tzdata(self):
-        import tzdata
         import tzlocal
-        del tzlocal, tzdata
+        del tzlocal

     def test_chardet(self):
         from calibre_extensions.uchardet import detect