Merge commit 'd435f549fe9bbfbea64ed9be36104e7a23f9603c' as 'libraries/action-scheduler'

libraries/action-scheduler/tests/phpunit/lock/ActionScheduler_OptionLock_Test.php

@@ -0,0 +1,77 @@
+<?php
+
+/**
+ * Class ActionScheduler_Lock_Test
+ * @package test_cases\lock
+ */
+class ActionScheduler_OptionLock_Test extends ActionScheduler_UnitTestCase {
+	public function test_instance() {
+		$lock = ActionScheduler::lock();
+		$this->assertInstanceOf( 'ActionScheduler_Lock', $lock );
+		$this->assertInstanceOf( 'ActionScheduler_OptionLock', $lock );
+	}
+
+	public function test_is_locked() {
+		$lock      = ActionScheduler::lock();
+		$lock_type = md5( wp_rand() );
+
+		$this->assertFalse( $lock->is_locked( $lock_type ) );
+
+		$lock->set( $lock_type );
+		$this->assertTrue( $lock->is_locked( $lock_type ) );
+	}
+
+	public function test_set() {
+		$lock      = ActionScheduler::lock();
+		$lock_type = md5( wp_rand() );
+
+		$lock->set( $lock_type );
+		$this->assertTrue( $lock->is_locked( $lock_type ) );
+	}
+
+	public function test_get_expiration() {
+		$lock      = ActionScheduler::lock();
+		$lock_type = md5( wp_rand() );
+
+		$lock->set( $lock_type );
+
+		$expiration   = $lock->get_expiration( $lock_type );
+		$current_time = time();
+
+		$this->assertGreaterThanOrEqual( 0, $expiration );
+		$this->assertGreaterThan( $current_time, $expiration );
+		$this->assertLessThan( $current_time + MINUTE_IN_SECONDS + 1, $expiration );
+	}
+
+	/**
+	 * A call to `ActionScheduler::lock()->set()` should fail if the lock is already held (ie, by another process).
+	 *
+	 * @return void
+	 */
+	public function test_lock_resists_race_conditions() {
+		global $wpdb;
+
+		$lock = ActionScheduler::lock();
+		$type = md5( wp_rand() );
+
+		// Approximate conditions in which a concurrently executing request manages to set (and obtain) the lock
+		// immediately before the current request can do so.
+		$simulate_concurrent_claim = function ( $query ) use ( $lock, $type ) {
+			static $executed = false;
+
+			if ( ! $executed && false !== strpos( $query, 'action_scheduler_lock_' ) && 0 === strpos( $query, 'INSERT INTO' ) ) {
+				$executed = true;
+				$lock->set( $type );
+			}
+
+			return $query;
+		};
+
+		add_filter( 'query', $simulate_concurrent_claim );
+		$wpdb->suppress_errors( true );
+		$this->assertFalse( $lock->is_locked( $type ), 'Initially, the lock is not held' );
+		$this->assertFalse( $lock->set( $type ), 'The lock was not obtained, because another process already claimed it.' );
+		$wpdb->suppress_errors( false );
+		remove_filter( 'query', $simulate_concurrent_claim );
+	}
+}