# mongo_drop
[](https://crates.io/crates/mongo_drop)
[](https://docs.rs/mongo_drop)
A Rust library providing an RAII-style guard for MongoDB databases, designed for testing environments. It automatically rolls back changes made to the database within the guard's asynchronous scope using MongoDB change streams and the experimental `AsyncDrop` trait.
**🚨 WARNING: This crate relies on the experimental `async_drop` feature, which is only available on nightly Rust and is subject to change or removal. It is NOT suitable for production use. Use this crate for test helpers or experimentation only.**
## Usage
```rust
#[cfg(test)]
mod tests {
use mongodb::{Client, options::ClientOptions};
use mongo_drop::MongoDrop;
#[tokio::test]
async fn test_mongo_drop() {
// Initialize MongoDB
let client = Client::with_uri_str("mongodb://localhost:27017").await.unwrap();
let database = client.database("test_db");
// Create a MongoDrop guard
let _guard = MongoDrop::new(&database).await.unwrap();
// Perform database operations within the guard
let coll = database.collection("test_collection");
coll.insert_one(doc! { "key": "value" }).await.unwrap();
let record = coll.find_one(doc! {}).await.unwrap();
assert_eq!(record, Some(doc! { "key": "value" }));
// The changes will be rolled back automatically when the guard goes out of scope
}
}
```
## Features
- `tracing`: Enables tracing support for the library.
- **Automatic Rollback:** Leverages `AsyncDrop` to undo database changes automatically when the guard goes out of scope in an `async` function.
- **Change Stream Based:** Listens to MongoDB change streams to capture modification events.
- **Supports DML Rollback:** Undoes `Insert`, `Update`, `Delete`, and `Replace` operations using collected pre-images.
- **Test-Focused:** Designed to simplify database state management in integration tests.
## Requirements
- **Nightly Rust Toolchain:** You must use a nightly build of the Rust compiler (`rustup toolchain install nightly`).