In this case instead of creating a now index and pushing documents I think we can use one of the already existing indexes like the one with movies (SHARED_DOCUMENTS) crates/meilisearch/tests/common/mod.rs:228

async fn error_update_existing_primary_key() {
    let index = shared_index_with_documents().await;

    let (update_task, code) = index.update(Some("primary")).await;

index.update() is missing for &Index<Shared>. It is available only for Index<Owned>.

Oh yeah, I see you're right.

Do you think you could create a new update_fail method similar to this one?

It didn't work with:

pub async fn update_index_fail(&self) -> (Value, StatusCode) {
        let (mut task, code) = self._update_settings(Value(serde_json::Value::Object(Default::default()))).await;
        if code.is_success() {
            task = self.wait_task(task.uid()).await;
            if task.is_success() {
                panic!(
                    "`update_index_fail` succeeded: {}",
                    serde_json::to_string_pretty(&task).unwrap()
                );
            }
        }
        (task, code)
    }

I will continue on it soon!

Ah yes, but it's because you tried to update the settings here:

        let (mut task, code) = self._update_settings(Value(serde_json::Value::Object(Default::default()))).await;

You should create your own _update around here that contains the code of the function currently specialized for the Owned index.

Then you can create the update_index_fail function the right way and update the original update function to make it call your _update wrapper.

Once this is done I think you'll be the only other person that entirely knows how to update the tests in all cases 😅

Same here, we could use the special nonexistent index that already exists instead of making a unique index