tests/util/test_app: Increase default database connection pool size

Before rust-lang#7244 we were limited to only having a single database connection in most of our test suite since we were working within a running transaction. This is no longer the case and e.g. our background jobs might use another connection from the pool, while the runner itself already holds a connection with a transaction.

This commit changes the default pool size to 5. Since the connections are opened on demand in the background it should not significantly influence the test performance.

Author: Turbo87

src/tests/util/test_app.rs

@@ -381,7 +381,7 @@ fn simple_config() -> config::Server {
         primary: DbPoolConfig {
             url: required_var("TEST_DATABASE_URL").unwrap().into(),
             read_only_mode: false,
-            pool_size: 1,
+            pool_size: 5,
             min_idle: None,
         },
         replica: None,