fix(test): make test_readonly_node_gc more robust

Signed-off-by: Yuchen Liang <yuchen@neon.tech>

compute_tools/src/bin/compute_ctl.rs

@@ -330,6 +330,7 @@ fn wait_spec(
         build_tag,
     };
     let compute = Arc::new(compute_node);
+    launch_lsn_lease_bg_task_for_static(&compute);
 
     // If this is a pooled VM, prewarm before starting HTTP server and becoming
     // available for binding. Prewarming helps Postgres start quicker later,
@@ -372,8 +373,6 @@ fn wait_spec(
         state.start_time = now;
     }
 
-    launch_lsn_lease_bg_task_for_static(&compute);
-
     Ok(WaitSpecResult {
         compute,
         http_port,

test_runner/regress/test_readonly_node.py

@@ -122,7 +122,8 @@ def test_readonly_node(neon_simple_env: NeonEnv):
         )
 
 
-def test_readonly_node_gc(neon_env_builder: NeonEnvBuilder):
+@pytest.mark.parametrize("iter", [i for i in range(20)])
+def test_readonly_node_gc(neon_env_builder: NeonEnvBuilder, iter: int):
     """
     Test static endpoint is protected from GC by acquiring and renewing lsn leases.
     """
@@ -267,7 +268,7 @@ def test_readonly_node_gc(neon_env_builder: NeonEnvBuilder):
                 time.sleep(LSN_LEASE_LENGTH / 2)
                 ps.start()
 
-            trigger_gc_and_select(
+            offset = trigger_gc_and_select(
                 env,
                 ep_static,
                 lease_lsn=lsn,