Add test for #323

postgres/Cargo.toml

@@ -40,4 +40,5 @@ tokio-postgres = { version = "0.7.9", default-features = false }
 config = { version = "0.14", features = ["json"] }
 dotenvy = "0.15.0"
 futures = "0.3.1"
+futures-util = "0.3.30"
 tokio = { version = "1.0", features = ["macros", "rt-multi-thread"] }

postgres/tests/async_trait.rs

@@ -0,0 +1,26 @@
+// This code must compile even without the async_trait crate
+// See: https://github.com/bikeshedder/deadpool/issues/323
+
+use deadpool_postgres::{tokio_postgres::Row, GenericClient};
+use futures_util::{Stream, StreamExt};
+use std::future::Future;
+use tokio_postgres::types::ToSql;
+
+// this function borrowed from tokio_postgres source code
+fn slice_iter<'a>(
+    s: &'a [&'a (dyn ToSql + Sync)],
+) -> impl ExactSizeIterator<Item = &'a dyn ToSql> + 'a {
+    s.iter().map(|s| *s as _)
+}
+
+pub trait PgQuery {
+    fn query_raw(
+        db: &impl GenericClient,
+        params: &[&(dyn ToSql + Sync)],
+    ) -> impl Future<Output = impl Stream<Item = Row>> + Send {
+        async {
+            let rows = db.query_raw("SELECT 1", slice_iter(params)).await.unwrap();
+            rows.map(|row| row.unwrap())
+        }
+    }
+}