add test for fetch one messing up stream states

tests/mysql.rs

@@ -210,3 +210,21 @@ async fn pool_smoke_test() -> anyhow::Result<()> {
 
     Ok(())
 }
+
+#[cfg_attr(feature = "runtime-async-std", async_std::test)]
+#[cfg_attr(feature = "runtime-tokio", tokio::test)]
+async fn test_fetch_one_and_ping() -> anyhow::Result<()> {
+    let mut conn = new::<MySql>().await?;
+
+    let (_id,): (i32,) = sqlx::query_as("SELECT 1 as id")
+        .fetch_one(&mut conn)
+        .await?;
+
+    conn.ping().await?;
+
+    let (_id,): (i32,) = sqlx::query_as("SELECT 1 as id")
+        .fetch_one(&mut conn)
+        .await?;
+
+    Ok(())
+}