is it possible to mock a Arc::new(self.clone()) in the trait?

[ymwjbxxq]

Hello,

I am in a tricky situation where I need to pass the mock itself to the return of the mock.

My trait:

#[async_trait]
impl MyTrait for MyStruct {
    async fn add_query(&self, item: &AnotherStruct) -> Result<(), ApplicationError> {
        self.query.execute(item).await
    }

    fn clone_to_arc(&self) -> Arc<dyn MyTrait> {
        Arc::new(self.clone())
    }
}

The code:

for record in event.payload.records.into_iter() {
        let shared_client = app_client.clone_to_arc();  // this mock is the problem

        tasks.push(tokio::spawn(async move {
            if let Some(body) = &record.body {
                let request = serde_json::from_str::<AnotherStruct>(&body);
                if let Ok(request) = request {
                    shared_client.add_slug_query(&request).await
                      .map_or_else(|e| {
                        println!("ERROR {:?}", e);
                      }, |_| ());
                }
            }
        }));
    }

The test has the following mock:

mock! {
            pub MyStruct {}
            #[async_trait]
            impl MyTrait for MyStruct {
                async fn add_query(&self, item: &AnotherStruct) -> Result<(), ApplicationError>  {
                    Ok(())
                }

                fn clone_to_arc(&self) -> Arc<dyn MyTrait> {
                    Arc::new(self.clone())
                }
            }
        }

let app_client = Init()  // this is not a mock but the concrete

let mut mock = MockMyStruct::default();
mock.add_query().times(1).returning(move |_| Ok(()));
mock.expect_clone_to_arc().times(1).returning(move || app_client.clone_to_arc());

Because I cannot find the way to simulate the self.clone for the mock.expect_clone_to_arc(), it is returning something different from the mock, and of course, I get the exception:
MockMyStruct::add_query: Expectation() called 0 time(s) which is fewer than expected 1

removing .times(1) will make the test pass but it is not correct.

Question:
is it possible to mock:

fn clone_to_arc(&self) -> Arc<dyn MyTrait> {
        Arc::new(self.clone())
    }

Thanks,
Dan

[ymwjbxxq]

I would like to have a professional opinion (it is my second day with mockAll) on how I solve the issue:

         let mut mock = MockMyStruct::default();
        //mock.expect_add_query().times(1).returning(move |_| Ok(()));
        mock.expect_clone_to_arc().times(1).returning(move || {
            let mut m = MockMyStruct::new();
            m.expect_add_query().times(1).returning(|_| Ok(())); // .times(1) is not working  I can put 100 and it still fine
            Arc::new(m)
        });

Does it make sense, or there is a better way to do it?

[asomers]

Yes, that's the best way to do it.

[ymwjbxxq]

Could you tell me why at that point

// .times(1) is not working I can put 100 and it still fine

[asomers]

Probably because the mock.clone_to_arc never gets called, so the inner mock never gets created, and its expectation never set.

[ymwjbxxq]

Strange because I think it is the first mock used, and from there, I set the second one.

let mut mock = MockMyStruct::default();
        mock.expect_clone_to_arc().times(1).returning(move || {
            let mut m = MockMyStruct::new();
            m. expect_add_query().times(1).returning(|_| Err(ApplicationError::InternalError(format!("something bad {}", "booom".to_string()))));
            Arc::new(m)
        });

The return of the second mock works, so it is just the times(N) that are not respected. Not a biggy for me.