diff --git a/test/ModelSpec.hs b/test/ModelSpec.hs
index 0f8597d0f..d3b8698e4 100644
--- a/test/ModelSpec.hs
+++ b/test/ModelSpec.hs
@@ -114,6 +114,7 @@ instance Arbitrary User where
     userFirstName <- unwords <$> sublistOf names
     userTitle <- fmap (pack . getPrintableString) <$> arbitrary
     userSex <- arbitrary
+    userBirthday <- arbitrary
 
     userMaxFavourites <- getNonNegative <$> arbitrary
     userMaxFavouriteTerms <- getNonNegative <$> arbitrary