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Mihai's questions

Martin Hope
Mihai
Asked: 2024-11-04 04:33:14 +0800 CST
  • 6

我正在实现命令模式的实现，其中订阅者将从读取器线程接收数据，并且我在使用 Rust mocks 测试我的实现时遇到了问题。请考虑这个简化的示例：

use std::thread;

pub trait Subscriber: Sync + Send {
    fn callback(&self);
}

pub struct Publisher {
    thread_handler: Option<thread::JoinHandle<()>>,
}

impl Publisher {
    pub fn new() -> Self {
        Self {
            thread_handler: None,
        }
    }

    pub fn start(&mut self, sub: Box<dyn Subscriber>) {
        self.thread_handler = Some(thread::spawn(move || {
            sub.callback();
        }));
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use mockall::*;

    mock! {
        TestSubscriber {}

        impl Subscriber for TestSubscriber {
            fn callback(&self);
        }
    }

    #[test]
    fn test_subscriber() {
        let mut publisher = Publisher::new();

        let mut mock_test_subscriber = Box::new(MockTestSubscriber::new());

        publisher.start(mock_test_subscriber);

        mock_test_subscriber.expect_callback().times(1);

        thread::sleep(std::time::Duration::from_millis(10));
    }
}

这会引发

error[E0382]: borrow of moved value: `mock_test_subscriber`
  --> src/foo.rs:46:9
   |
42 |         let mut mock_test_subscriber = Box::new(MockTestSubscriber::new());
   |             ------------------------ move occurs because `mock_test_subscriber` has type `Box<MockTestSubscriber>`, which does not implement the `Copy` trait
43 |
44 |         publisher.start(mock_test_subscriber);
   |                           -------------------- value moved here
45 |
46 |         mock_test_subscriber.expect_callback().times(1);
   |         ^^^^^^^^^^^^^^^^^^^^ value borrowed here after move

我真的不知道如何解决这个问题，我尝试过绕过它dyn Subscriber，Arc但仍然无法让它工作。任何建议都将不胜感激。或者也许有更好的设计来实现相同的结果。

multithreading