Fix flaky Find_Or_Create_Snapshot tests under random ordering

The tests failed intermittently in CI depending on the PHPUnit random
seed. Test_Find_Or_Create_Snapshot mocks archive.org at the HTTP layer
(pre_http_request), but several other test classes register fake clients
via the iawmlf_snapshot_client / iawmlf_link_checker_client filters and
only cleared them in set_up, never in tear_down. When one ran just before
Find_Or_Create, the stale client hijacked the event so get_latest_snapshot
returned null and the link stuck at 'pending' instead of 'new'/'done'.

- Defensive: clear both client filters in Find_Or_Create_Snapshot::set_up.
- Root cause: add tear_down cleanup to the set_up-only leakers
  (Check_Snapshot_Status_Event, Action_Scheduler_Garbage_Collection,
  Report_Table_Actions).

Verified: the previously-failing seed 1782941233 now passes, plus three
further random seeds - 355 tests green each.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: gin0115

tests/Event/Test_Check_Snapshot_Status_Event.php

@@ -48,6 +48,17 @@ public function set_up(): void {
 		parent::set_up();
 	}
 
+	/**
+	 * Tear down
+	 */
+	public function tear_down(): void {
+		// Remove client mocks so they can't leak into later tests under random ordering.
+		remove_all_filters( 'iawmlf_snapshot_client' );
+		remove_all_filters( 'iawmlf_link_checker_client' );
+
+		parent::tear_down();
+	}
+
 	/**
 	 * Set the snapshot client to return a mocked response.
 	 *

tests/Event/Test_Find_Or_Create_Snapshot.php

@@ -32,6 +32,11 @@ public function set_up(): void {
 		// Clear the actionscheduler_actions table.
 		$this->wpdb->query( "TRUNCATE TABLE {$this->wpdb->prefix}actionscheduler_actions" );
 
+		// Clear any snapshot / link-checker client mocks leaked from other tests (random order):
+		// this class mocks at the HTTP layer, so a stale injected client would leave links 'pending'.
+		remove_all_filters( 'iawmlf_snapshot_client' );
+		remove_all_filters( 'iawmlf_link_checker_client' );
+
 		parent::set_up();
 	}
 

tests/Report/Test_Report_Table_Actions.php

@@ -49,6 +49,17 @@ public function set_up(): void {
 		parent::set_up();
 	}
 
+	/**
+	 * Tear down
+	 */
+	public function tear_down(): void {
+		// Remove client mocks so they can't leak into later tests under random ordering.
+		remove_all_filters( 'iawmlf_snapshot_client' );
+		remove_all_filters( 'iawmlf_link_checker_client' );
+
+		parent::tear_down();
+	}
+
 	/**
 	 * Set the snapshot client to return a mocked response.
 	 *

tests/Util/Test_Action_Scheduler_Garbage_Collection.php

@@ -55,6 +55,17 @@ public function set_up(): void {
 		parent::set_up();
 	}
 
+	/**
+	 * Tear down
+	 */
+	public function tear_down(): void {
+		// Remove client mocks so they can't leak into later tests under random ordering.
+		remove_all_filters( 'iawmlf_snapshot_client' );
+		remove_all_filters( 'iawmlf_link_checker_client' );
+
+		parent::tear_down();
+	}
+
 	/**
 	 * Set the snapshot client to return a mocked response.
 	 *