diff --git a/tests/qapi-schema/test-qapi.py b/tests/qapi-schema/test-qapi.py
index 2160cef082..d58c31f539 100755
--- a/tests/qapi-schema/test-qapi.py
+++ b/tests/qapi-schema/test-qapi.py
@@ -206,6 +206,7 @@ def main(argv):
     parser.add_argument('-d', '--dir', action='store', default='',
                         help="directory containing tests")
     parser.add_argument('-u', '--update', action='store_true',
+                        default='QAPI_TEST_UPDATE' in os.environ,
                         help="update expected test results")
     parser.add_argument('tests', nargs='*', metavar='TEST', action='store')
     args = parser.parse_args()