Wait for test Postgres readiness

crates/crank-test-support/src/lib.rs

@@ -7,6 +7,7 @@ use sqlx::{Connection, Executor, PgConnection};
 use testcontainers::{Container, ImageExt, runners::SyncRunner};
 use testcontainers_modules::postgres::Postgres;
 use tokio::sync::OnceCell;
+use tokio::time::{Duration, sleep};
 
 static POSTGRES: OnceCell<TestPostgres> = OnceCell::const_new();
 static CLEANUP_REGISTERED: OnceLock<()> = OnceLock::new();
@@ -24,9 +25,7 @@ pub async fn postgres_database_url() -> &'static str {
 pub async fn postgres_schema_url(prefix: &str) -> String {
     let database_url = postgres_database_url().await;
     let schema = unique_schema_name(prefix);
-    let mut connection = PgConnection::connect(database_url)
+    let mut connection = connect_admin_with_retry(database_url).await;
-        .await
-        .expect("test PostgreSQL container must accept admin connections");
 
     connection
         .execute(sqlx::query(&format!("create schema {schema}")))
@@ -36,6 +35,27 @@ pub async fn postgres_schema_url(prefix: &str) -> String {
     format!("{database_url}?options=-csearch_path%3D{schema}")
 }
 
+async fn connect_admin_with_retry(database_url: &str) -> PgConnection {
+    let mut last_error = None;
+
+    for _ in 0..80 {
+        match PgConnection::connect(database_url).await {
+            Ok(connection) => return connection,
+            Err(error) => {
+                last_error = Some(error);
+                sleep(Duration::from_millis(250)).await;
+            }
+        }
+    }
+
+    panic!(
+        "test PostgreSQL container must accept admin connections after readiness wait: {}",
+        last_error
+            .map(|error| error.to_string())
+            .unwrap_or_else(|| "connection was not attempted".to_owned())
+    );
+}
+
 pub fn unique_schema_name(prefix: &str) -> String {
     let normalized_prefix: String = prefix
         .chars()