diff --git a/tests-extra/tools/dnstest/zonefile.py b/tests-extra/tools/dnstest/zonefile.py
index d1eaad3a5690b8b410205c1e3c6fd258d0daf12f..1f14b725a784e9c303d1b8beb736ab62b865b1dc 100644
--- a/tests-extra/tools/dnstest/zonefile.py
+++ b/tests-extra/tools/dnstest/zonefile.py
@@ -94,7 +94,9 @@ class ZoneFile(object):
                 prepare_dir(self.key_dir)
                 params = ["-s", "-3", "y" if nsec3 else "n", "-k", self.key_dir] \
                          + params
-            zone_generate.main(params)
+            if zone_generate.main(params) != 0:
+                raise OSError
+            
         except OSError:
             raise Exception("Can't create zone file '%s'" % self.path)