tests: remove redundant wait_while (#4952)

Remove redundant `wait_while` in tests. It had only one usage. Use
`wait_tenant_status404`.

Related:
https://github.com/neondatabase/neon/pull/4855#discussion_r1289610641

test_runner/fixtures/pageserver/utils.py

@@ -19,15 +19,6 @@ def assert_tenant_state(
     assert tenant_status["state"]["slug"] == expected_state, message or tenant_status
 
 
-def tenant_exists(pageserver_http: PageserverHttpClient, tenant_id: TenantId):
-    tenants = pageserver_http.tenant_list()
-    matching = [t for t in tenants if TenantId(t["id"]) == tenant_id]
-    assert len(matching) < 2
-    if len(matching) == 0:
-        return None
-    return matching[0]
-
-
 def remote_consistent_lsn(
     pageserver_http: PageserverHttpClient, tenant: TenantId, timeline: TimelineId
 ) -> Lsn:
@@ -258,6 +249,7 @@ def wait_tenant_status_404(
     pageserver_http: PageserverHttpClient,
     tenant_id: TenantId,
     iterations: int,
+    interval: float = 0.250,
 ):
     def tenant_is_missing():
         data = {}
@@ -271,7 +263,7 @@ def wait_tenant_status_404(
 
         raise RuntimeError(f"Timeline exists state {data.get('state')}")
 
-    wait_until(iterations, interval=0.250, func=tenant_is_missing)
+    wait_until(iterations, interval=interval, func=tenant_is_missing)
 
 
 def tenant_delete_wait_completed(

test_runner/fixtures/utils.py

@@ -303,22 +303,6 @@ def wait_until(number_of_iterations: int, interval: float, func: Fn):
     raise Exception("timed out while waiting for %s" % func) from last_exception
 
 
-def wait_while(number_of_iterations: int, interval: float, func):
-    """
-    Wait until 'func' returns false, or throws an exception.
-    """
-    for i in range(number_of_iterations):
-        try:
-            if not func():
-                return
-            log.info("waiting for %s iteration %s failed", func, i + 1)
-            time.sleep(interval)
-            continue
-        except Exception:
-            return
-    raise Exception("timed out while waiting for %s" % func)
-
-
 def run_pg_bench_small(pg_bin: "PgBin", connstr: str):
     """
     Fast way to populate data.

test_runner/regress/test_tenant_relocation.py

@@ -17,9 +17,9 @@ from fixtures.neon_fixtures import (
 from fixtures.pageserver.http import PageserverHttpClient
 from fixtures.pageserver.utils import (
     assert_tenant_state,
-    tenant_exists,
     wait_for_last_record_lsn,
     wait_for_upload,
+    wait_tenant_status_404,
 )
 from fixtures.port_distributor import PortDistributor
 from fixtures.remote_storage import RemoteStorageKind, available_remote_storages
@@ -29,7 +29,6 @@ from fixtures.utils import (
     start_in_background,
     subprocess_capture,
     wait_until,
-    wait_while,
 )
 
 
@@ -269,11 +268,16 @@ def test_tenant_relocation(
 
     env = neon_env_builder.init_start()
 
+    tenant_id = TenantId("74ee8b079a0e437eb0afea7d26a07209")
+
     # FIXME: Is this expected?
     env.pageserver.allowed_errors.append(
         ".*init_tenant_mgr: marking .* as locally complete, while it doesnt exist in remote index.*"
     )
 
+    # Needed for detach polling.
+    env.pageserver.allowed_errors.append(f".*NotFound: tenant {tenant_id}.*")
+
     # create folder for remote storage mock
     remote_storage_mock_path = env.repo_dir / "local_fs_remote_storage"
 
@@ -283,9 +287,7 @@ def test_tenant_relocation(
 
     pageserver_http = env.pageserver.http_client()
 
-    tenant_id, initial_timeline_id = env.neon_cli.create_tenant(
-        TenantId("74ee8b079a0e437eb0afea7d26a07209")
-    )
+    _, initial_timeline_id = env.neon_cli.create_tenant(tenant_id)
     log.info("tenant to relocate %s initial_timeline_id %s", tenant_id, initial_timeline_id)
 
     env.neon_cli.create_branch("test_tenant_relocation_main", tenant_id=tenant_id)
@@ -469,11 +471,8 @@ def test_tenant_relocation(
         pageserver_http.tenant_detach(tenant_id)
 
         # Wait a little, so that the detach operation has time to finish.
-        wait_while(
-            number_of_iterations=100,
-            interval=1,
-            func=lambda: tenant_exists(pageserver_http, tenant_id),
-        )
+        wait_tenant_status_404(pageserver_http, tenant_id, iterations=100, interval=1)
+
         post_migration_check(ep_main, 500500, old_local_path_main)
         post_migration_check(ep_second, 1001000, old_local_path_second)