use mockiato::mockable; #[mockable] trait MessageSender { fn send_message(&self, recipient: &str, message: &str); } #[test] fn test() { let mut message_sender = MessageSenderMock::new(); message_sender .expect_send_message( |arg| arg.partial_eq("Jane"), |arg| arg.partial_eq("Don't make lemonade"), ) .times(1..) .returns(()); message_sender.send_message("Jane", "Don't make lemonade") }