diff --git a/CRM/Core/BAO/UserJob.php b/CRM/Core/BAO/UserJob.php
index 0f1c6835002b..f0a650b9fb3c 100644
--- a/CRM/Core/BAO/UserJob.php
+++ b/CRM/Core/BAO/UserJob.php
@@ -38,7 +38,7 @@ public static function on_civi_queue_check(\Civi\Core\Event\GenericHookEvent $e)
     /** @var \CRM_Queue_Queue $queue */
     $queue = $e->queue;
     $userJobId = static::findUserJobId($queue->getName());
-    if ($userJobId && $queue->numberOfItems() < 1) {
+    if ($userJobId && $queue->getStatistic('total') < 1) {
       $queue->setStatus('completed');
     }
   }
diff --git a/CRM/Queue/Queue.php b/CRM/Queue/Queue.php
index 9ff7d9b10c72..7dfc1cdd6a21 100644
--- a/CRM/Queue/Queue.php
+++ b/CRM/Queue/Queue.php
@@ -138,8 +138,28 @@ abstract public function createItem($data, $options = []);
    * Determine number of items remaining in the queue.
    *
    * @return int
-   */
-  abstract public function numberOfItems();
+   * @deprecated
+   *   Use `getStatistic(string $name)` instead.
+   *   The definition of `numberOfItems()` has become conflicted among different subclasses.
+   */
+  public function numberOfItems() {
+    // This is the statistic traditionally reported by core queue implementations.
+    // However, it may not be as useful, and subclasses may have different interpretations.
+    return $this->getStatistic('total');
+  }
+
+  /**
+   * Get summary information about items in the queue.
+   *
+   * @param string $name
+   *   The desired statistic. Ex:
+   *   - 'ready': The number of items ready for execution (not currently claimed, not scheduled for future).
+   *   - 'blocked': The number of items that may be runnable in the future, but cannot be run right now.
+   *   - 'total': The total number of items known to the queue, regardless of whether their current status.
+   * @return int|float|null
+   *   The value of the statistic, or NULL if the queue backend does not unsupport this statistic.
+   */
+  abstract public function getStatistic(string $name);
 
   /**
    * Get the next item.
diff --git a/CRM/Queue/Queue/Memory.php b/CRM/Queue/Queue/Memory.php
index 7fd1ab6ae211..e66791a5b8a7 100644
--- a/CRM/Queue/Queue/Memory.php
+++ b/CRM/Queue/Queue/Memory.php
@@ -110,12 +110,35 @@ public function createItem($data, $options = []) {
   }
 
   /**
-   * Determine number of items remaining in the queue.
-   *
-   * @return int
+   * @param string $name
+   * @return int|float|null
+   * @see \CRM_Queue_Queue::getStatistic()
    */
-  public function numberOfItems() {
-    return count($this->items);
+  public function getStatistic(string $name) {
+    $ready = function(): int {
+      $now = CRM_Utils_Time::time();
+      $ready = 0;
+      foreach ($this->items as $id => $item) {
+        if (empty($this->releaseTimes[$id]) || $this->releaseTimes[$id] <= $now) {
+          $ready++;
+        }
+      }
+      return $ready;
+    };
+
+    switch ($name) {
+      case 'ready':
+        return $ready();
+
+      case 'blocked':
+        return count($this->items) - $ready();
+
+      case 'total':
+        return count($this->items);
+
+      default:
+        return NULL;
+    }
   }
 
   /**
diff --git a/CRM/Queue/Queue/SqlTrait.php b/CRM/Queue/Queue/SqlTrait.php
index 886eafa0c323..69f5cf220689 100644
--- a/CRM/Queue/Queue/SqlTrait.php
+++ b/CRM/Queue/Queue/SqlTrait.php
@@ -47,22 +47,34 @@ public function deleteQueue() {
    * @return bool
    */
   public function existsQueue() {
-    return ($this->numberOfItems() > 0);
+    return ($this->getStatistic('total') > 0);
   }
 
   /**
-   * Determine number of items remaining in the queue.
-   *
-   * @return int
+   * @param string $name
+   * @return int|float|null
+   * @see \CRM_Queue_Queue::getStatistic()
    */
-  public function numberOfItems() {
-    return CRM_Core_DAO::singleValueQuery("
-      SELECT count(*)
-      FROM civicrm_queue_item
-      WHERE queue_name = %1
-    ", [
-      1 => [$this->getName(), 'String'],
-    ]);
+  public function getStatistic(string $name) {
+    switch ($name) {
+      case 'ready':
+        return (int) CRM_Core_DAO::singleValueQuery(
+          'SELECT count(*) FROM civicrm_queue_item WHERE queue_name = %1 AND (release_time is null OR release_time <= FROM_UNIXTIME(%2))',
+          [1 => [$this->getName(), 'String'], 2 => [CRM_Utils_Time::time(), 'Int']]);
+
+      case 'blocked':
+        return (int) CRM_Core_DAO::singleValueQuery(
+          'SELECT count(*) FROM civicrm_queue_item WHERE queue_name = %1 AND release_time > FROM_UNIXTIME(%2)',
+          [1 => [$this->getName(), 'String'], 2 => [CRM_Utils_Time::time(), 'Int']]);
+
+      case 'total':
+        return (int) CRM_Core_DAO::singleValueQuery(
+          'SELECT count(*) FROM civicrm_queue_item WHERE queue_name = %1',
+          [1 => [$this->getName(), 'String']]);
+
+      default:
+        return NULL;
+    }
   }
 
   /**
diff --git a/Civi/Test/QueueTestTrait.php b/Civi/Test/QueueTestTrait.php
new file mode 100644
index 000000000000..6b0290e4f7d1
--- /dev/null
+++ b/Civi/Test/QueueTestTrait.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Civi\Test;
+
+/**
+ * Helper functions for testing queues.
+ */
+trait QueueTestTrait {
+
+  protected function assertQueueStats(int $total, int $ready, int $blocked, \CRM_Queue_Queue $queue) {
+    $format = 'total=%d ready=%d blocked=%d';
+    $expect = [$total, $ready, $blocked];
+    $actual = [$queue->getStatistic('total'), $queue->getStatistic('ready'), $queue->getStatistic('blocked')];
+    $this->assertEquals(sprintf($format, ...$expect), sprintf($format, ...$actual));
+
+    // Deprecated - but checking for continuity.
+    $this->assertEquals($total, $queue->numberOfItems());
+  }
+
+}
diff --git a/templates/CRM/Queue/Page/Runner.tpl b/templates/CRM/Queue/Page/Runner.tpl
index e7ade413415e..620b834c0e47 100644
--- a/templates/CRM/Queue/Page/Runner.tpl
+++ b/templates/CRM/Queue/Page/Runner.tpl
@@ -63,7 +63,7 @@ CRM.$(function($) {
     if (!data.is_error) {
       queueRunnerData.completed++;
     }
-    if (data.numberOfItems) {
+    if ('numberOfItems' in data && data.numberOfItems !== null) {
       queueRunnerData.numberOfItems = parseInt(data.numberOfItems);
     }
 
diff --git a/tests/phpunit/CRM/Queue/Queue/SqlTest.php b/tests/phpunit/CRM/Queue/Queue/SqlTest.php
index 3fb7e3965232..6de10ed62213 100644
--- a/tests/phpunit/CRM/Queue/Queue/SqlTest.php
+++ b/tests/phpunit/CRM/Queue/Queue/SqlTest.php
@@ -18,6 +18,8 @@
  */
 class CRM_Queue_Queue_SqlTest extends CiviUnitTestCase {
 
+  use \Civi\Test\QueueTestTrait;
+
   /* ----------------------- Queue providers ----------------------- */
 
   /* Define a list of queue providers which should be tested */
@@ -73,12 +75,12 @@ public function testPriorities($queueSpec) {
       'test-key' => 'c',
     ]);
 
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('a', $item->data['test-key']);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('b', $item->data['test-key']);
     $this->queue->deleteItem($item);
@@ -103,27 +105,27 @@ public function testPriorities($queueSpec) {
       'test-key' => 'd',
     ]);
 
-    $this->assertEquals(4, $this->queue->numberOfItems());
+    $this->assertQueueStats(4, 4, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('start', $item->data['test-key']);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('c', $item->data['test-key']);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('d', $item->data['test-key']);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 1, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('end', $item->data['test-key']);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
 }
diff --git a/tests/phpunit/CRM/Queue/QueueTest.php b/tests/phpunit/CRM/Queue/QueueTest.php
index e3fe0010aa7f..3f1c6ac5b41c 100644
--- a/tests/phpunit/CRM/Queue/QueueTest.php
+++ b/tests/phpunit/CRM/Queue/QueueTest.php
@@ -16,6 +16,8 @@
  */
 class CRM_Queue_QueueTest extends CiviUnitTestCase {
 
+  use \Civi\Test\QueueTestTrait;
+
   /* ----------------------- Queue providers ----------------------- */
 
   /* Define a list of queue providers which should be tested */
@@ -25,19 +27,19 @@ class CRM_Queue_QueueTest extends CiviUnitTestCase {
    */
   public function getQueueSpecs() {
     $queueSpecs = [];
-    $queueSpecs[] = [
+    $queueSpecs['Sql'] = [
       [
         'type' => 'Sql',
         'name' => 'test-queue-sql',
       ],
     ];
-    $queueSpecs[] = [
+    $queueSpecs['Memory'] = [
       [
         'type' => 'Memory',
         'name' => 'test-queue-mem',
       ],
     ];
-    $queueSpecs[] = [
+    $queueSpecs['SqlParallel'] = [
       [
         'type' => 'SqlParallel',
         'name' => 'test-queue-sqlparallel',
@@ -163,35 +165,41 @@ public function testBasicUsage($queueSpec) {
       'test-key' => 'c',
     ]);
 
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
+
     $item = $this->queue->claimItem();
+    $this->assertQueueStats(3, 2, 1, $this->queue);
     $this->assertEquals('a', $item->data['test-key']);
     $this->assertEquals(1, $item->run_count);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
     $item = $this->queue->claimItem();
+    $this->assertQueueStats(2, 1, 1, $this->queue);
     $this->assertEquals('b', $item->data['test-key']);
     $this->assertEquals(1, $item->run_count);
     $this->queue->deleteItem($item);
+    $this->assertQueueStats(1, 1, 0, $this->queue);
 
     $this->queue->createItem([
       'test-key' => 'd',
     ]);
 
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
+
     $item = $this->queue->claimItem();
+    $this->assertQueueStats(2, 1, 1, $this->queue);
     $this->assertEquals('c', $item->data['test-key']);
     $this->assertEquals(1, $item->run_count);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 1, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('d', $item->data['test-key']);
     $this->assertEquals(1, $item->run_count);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   /**
@@ -211,16 +219,16 @@ public function testManualRelease($queueSpec) {
     $item = $this->queue->claimItem();
     $this->assertEquals('a', $item->data['test-key']);
     $this->assertEquals(1, $item->run_count);
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $this->queue);
     $this->queue->releaseItem($item);
 
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 1, 0, $this->queue);
     $item = $this->queue->claimItem();
     $this->assertEquals('a', $item->data['test-key']);
     $this->assertEquals(2, $item->run_count);
     $this->queue->deleteItem($item);
 
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   /**
@@ -238,11 +246,12 @@ public function testTimeoutRelease($queueSpec) {
     $this->queue->createItem([
       'test-key' => 'a',
     ]);
+    $this->assertQueueStats(1, 1, 0, $this->queue);
 
     $item = $this->queue->claimItem();
     $this->assertEquals('a', $item->data['test-key']);
     $this->assertEquals(1, $item->run_count);
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $this->queue);
     // forget to release
 
     // haven't reach expiration yet
@@ -255,10 +264,10 @@ public function testTimeoutRelease($queueSpec) {
     $item3 = $this->queue->claimItem();
     $this->assertEquals('a', $item3->data['test-key']);
     $this->assertEquals(2, $item3->run_count);
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $this->queue);
     $this->queue->deleteItem($item3);
 
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   /**
@@ -279,7 +288,7 @@ public function testStealItem($queueSpec) {
     $item = $this->queue->claimItem();
     $this->assertEquals('a', $item->data['test-key']);
     $this->assertEquals(1, $item->run_count);
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $this->queue);
     // forget to release
 
     // haven't reached expiration yet, so claimItem fails
@@ -291,10 +300,10 @@ public function testStealItem($queueSpec) {
     $item3 = $this->queue->stealItem();
     $this->assertEquals('a', $item3->data['test-key']);
     $this->assertEquals(2, $item3->run_count);
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $this->queue);
     $this->queue->deleteItem($item3);
 
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   /**
@@ -385,13 +394,13 @@ public function testCreateResetTrue($queueSpec) {
     $this->queue->createItem([
       'test-key' => 'b',
     ]);
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
     unset($this->queue);
 
     $queue2 = $this->queueService->create(
       $queueSpec + ['reset' => TRUE]
     );
-    $this->assertEquals(0, $queue2->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue2);
   }
 
   /**
@@ -408,11 +417,11 @@ public function testCreateResetFalse($queueSpec) {
     $this->queue->createItem([
       'test-key' => 'b',
     ]);
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
     unset($this->queue);
 
     $queue2 = $this->queueService->create($queueSpec);
-    $this->assertEquals(2, $queue2->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $queue2);
 
     $item = $queue2->claimItem();
     $this->assertEquals('a', $item->data['test-key']);
@@ -433,11 +442,11 @@ public function testLoad($queueSpec) {
     $this->queue->createItem([
       'test-key' => 'b',
     ]);
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
     unset($this->queue);
 
     $queue2 = $this->queueService->create($queueSpec);
-    $this->assertEquals(2, $queue2->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $queue2);
 
     $item = $queue2->claimItem();
     $this->assertEquals('a', $item->data['test-key']);
@@ -460,12 +469,12 @@ public function testBatchClaim($queueSpec) {
     for ($i = 0; $i < 9; $i++) {
       $this->queue->createItem('x' . $i);
     }
-    $this->assertEquals(9, $this->queue->numberOfItems());
+    $this->assertQueueStats(9, 9, 0, $this->queue);
 
     // We expect this driver to be fully compliant with batching.
     $claimsA = $this->queue->claimItems(3);
     $claimsB = $this->queue->claimItems(3);
-    $this->assertEquals(9, $this->queue->numberOfItems());
+    $this->assertQueueStats(9, 3, 6, $this->queue);
 
     $this->assertEquals(['x0', 'x1', 'x2'], CRM_Utils_Array::collect('data', $claimsA));
     $this->assertEquals(['x3', 'x4', 'x5'], CRM_Utils_Array::collect('data', $claimsB));
@@ -474,24 +483,24 @@ public function testBatchClaim($queueSpec) {
     $this->queue->releaseItems([$claimsA[2]]); /* x2: will retry with next claimItems() */
     $this->queue->deleteItems([$claimsB[0], $claimsB[1]]); /* x3, x4 */
     /* claimsB[2]: x5: Oops, we're gonna take some time to finish this one. */
-    $this->assertEquals(5, $this->queue->numberOfItems());
+    $this->assertQueueStats(5, 4, 1, $this->queue);
 
     $claimsC = $this->queue->claimItems(3);
     $this->assertEquals(['x2', 'x6', 'x7'], CRM_Utils_Array::collect('data', $claimsC));
     $this->queue->deleteItem($claimsC[0]); /* x2 */
     $this->queue->releaseItem($claimsC[1]); /* x6: will retry with next claimItems() */
     $this->queue->deleteItem($claimsC[2]); /* x7 */
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 2, 1, $this->queue);
 
     $claimsD = $this->queue->claimItems(3);
     $this->assertEquals(['x6', 'x8'], CRM_Utils_Array::collect('data', $claimsD));
     $this->queue->deleteItem($claimsD[0]); /* x6 */
     $this->queue->deleteItem($claimsD[1]); /* x8 */
-    $this->assertEquals(1, $this->queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $this->queue);
 
     // claimsB took a while to wrap-up. But it finally did!
     $this->queue->deleteItem($claimsB[2]); /* x5 */
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   public function testSetStatus() {
diff --git a/tests/phpunit/CRM/Queue/RunnerTest.php b/tests/phpunit/CRM/Queue/RunnerTest.php
index 8581edd14ef3..a179fa9d51b9 100644
--- a/tests/phpunit/CRM/Queue/RunnerTest.php
+++ b/tests/phpunit/CRM/Queue/RunnerTest.php
@@ -16,6 +16,8 @@
  */
 class CRM_Queue_RunnerTest extends CiviUnitTestCase {
 
+  use \Civi\Test\QueueTestTrait;
+
   public function setUp(): void {
     parent::setUp();
     $this->queueService = CRM_Queue_Service::singleton(TRUE);
@@ -61,11 +63,11 @@ public function testRunAllNormal() {
       'errorMode' => CRM_Queue_Runner::ERROR_ABORT,
     ]);
     $this->assertEquals(self::$_recordedValues, []);
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
     $result = $runner->runAll();
     $this->assertEquals(TRUE, $result);
     $this->assertEquals(self::$_recordedValues, ['a', 'b', 'c']);
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   /**
@@ -97,11 +99,11 @@ public function testRunAll_AddMore() {
       'errorMode' => CRM_Queue_Runner::ERROR_ABORT,
     ]);
     $this->assertEquals(self::$_recordedValues, []);
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
     $result = $runner->runAll();
     $this->assertEquals(TRUE, $result);
     $this->assertEquals(self::$_recordedValues, ['a', 1, 2, 3, 'b']);
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   /**
@@ -132,12 +134,13 @@ public function testRunAll_Continue_Exception() {
       'errorMode' => CRM_Queue_Runner::ERROR_CONTINUE,
     ]);
     $this->assertEquals(self::$_recordedValues, []);
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
+
     $result = $runner->runAll();
     // FIXME useless return
     $this->assertEquals(TRUE, $result);
     $this->assertEquals(self::$_recordedValues, ['a', 'c']);
-    $this->assertEquals(0, $this->queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $this->queue);
   }
 
   /**
@@ -168,13 +171,14 @@ public function testRunAll_Abort_Exception() {
       'errorMode' => CRM_Queue_Runner::ERROR_ABORT,
     ]);
     $this->assertEquals(self::$_recordedValues, []);
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
+
     $result = $runner->runAll();
     $this->assertEquals(1, $result['is_error']);
     // nothing from 'c'
     $this->assertEquals(self::$_recordedValues, ['a']);
     // 'b' and 'c' remain
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
   }
 
   /**
@@ -205,13 +209,13 @@ public function testRunAll_Abort_False() {
       'errorMode' => CRM_Queue_Runner::ERROR_ABORT,
     ]);
     $this->assertEquals(self::$_recordedValues, []);
-    $this->assertEquals(3, $this->queue->numberOfItems());
+    $this->assertQueueStats(3, 3, 0, $this->queue);
     $result = $runner->runAll();
     $this->assertEquals(1, $result['is_error']);
     // nothing from 'c'
     $this->assertEquals(self::$_recordedValues, ['a']);
     // 'b' and 'c' remain
-    $this->assertEquals(2, $this->queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $this->queue);
   }
 
   /**
diff --git a/tests/phpunit/api/v4/Entity/QueueTest.php b/tests/phpunit/api/v4/Entity/QueueTest.php
index 6f74de2eccc8..3656eb1ff8f5 100644
--- a/tests/phpunit/api/v4/Entity/QueueTest.php
+++ b/tests/phpunit/api/v4/Entity/QueueTest.php
@@ -22,6 +22,7 @@
 use Civi\Api4\Queue;
 use Civi\Api4\UserJob;
 use Civi\Core\Event\GenericHookEvent;
+use Civi\Test\QueueTestTrait;
 
 /**
  * @group headless
@@ -29,6 +30,8 @@
  */
 class QueueTest extends Api4TestBase {
 
+  use QueueTestTrait;
+
   protected function setUp(): void {
     \Civi::$statics[__CLASS__] = [
       'doSomethingResult' => TRUE,
@@ -56,7 +59,7 @@ public function testBasicLinearPolling() {
       'retry_limit' => 2,
       'retry_interval' => 4,
     ]);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
@@ -98,13 +101,13 @@ public function testBasicLinearPolling() {
     $this->assertEquals(['first_ok', 'second_err', 'second_ok'], \Civi::$statics[__CLASS__]['doSomethingLog']);
 
     // All done.
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
   }
 
   public function testBasicParallelPolling() {
     $queueName = 'QueueTest_' . md5(random_bytes(32)) . '_parallel';
     $queue = \Civi::queue($queueName, ['type' => 'SqlParallel', 'runner' => 'task', 'error' => 'delete']);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
@@ -129,7 +132,7 @@ public function testBasicParallelPolling() {
     Queue::runItems(0)->setItems([$first])->execute();
     $this->assertEquals(['second_ok', 'first_ok'], \Civi::$statics[__CLASS__]['doSomethingLog']);
 
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
   }
 
   /**
@@ -149,7 +152,7 @@ public function testBatchParallelPolling() {
       'error' => 'delete',
       'batch_limit' => 3,
     ]);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     for ($i = 0; $i < 7; $i++) {
       \Civi::queue($queueName)->createItem(['thingy' => $i]);
@@ -189,7 +192,7 @@ function($item) {
   public function testSelect() {
     $queueName = 'QueueTest_' . md5(random_bytes(32)) . '_parallel';
     $queue = \Civi::queue($queueName, ['type' => 'SqlParallel', 'runner' => 'task', 'error' => 'delete']);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
@@ -205,7 +208,7 @@ public function testSelect() {
   public function testEmptyPoll() {
     $queueName = 'QueueTest_' . md5(random_bytes(32)) . '_linear';
     $queue = \Civi::queue($queueName, ['type' => 'Sql', 'runner' => 'task', 'error' => 'delete']);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     $startResult = Queue::claimItems()->setQueue($queueName)->execute();
     $this->assertEquals(0, $startResult->count());
@@ -225,14 +228,14 @@ public function getDelayableDrivers(): array {
   public function testDelayedStart(array $queueSpec) {
     $queueName = 'QueueTest_' . md5(random_bytes(32)) . '_delayed';
     $queue = \Civi::queue($queueName, $queueSpec);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     $releaseTime = \CRM_Utils_Time::strtotime('+3 seconds');
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
       ['itwillstartanymomentnow']
     ), ['release_time' => $releaseTime]);
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $queue);
 
     // Not available... yet...
     $claim1 = $queue->claimItem();
@@ -268,7 +271,7 @@ public function testRetryWithPoliteExhaustion(string $errorMode) {
       'retry_limit' => 2,
       'retry_interval' => 1,
     ]);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
@@ -311,28 +314,28 @@ public function testRetryWithDelinquencyAndSuccess() {
       'retry_interval' => 0,
       'lease_time' => 1,
     ]);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
       ['playinghooky']
     ));
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 1, 0, $queue);
 
     $claim1 = $this->waitForClaim(0.5, 5, $queueName);
     // Oops, don't do anything with claim #1!
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $queue);
     $this->assertEquals([], \Civi::$statics[__CLASS__]['doSomethingLog']);
 
     $claim2 = $this->waitForClaim(0.5, 5, $queueName);
     // Oops, don't do anything with claim #2!
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $queue);
     $this->assertEquals([], \Civi::$statics[__CLASS__]['doSomethingLog']);
 
     $claim3 = $this->waitForClaim(0.5, 5, $queueName);
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 0, 1, $queue);
     $result = Queue::runItems(0)->setItems([$claim3])->execute()->first();
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
     $this->assertEquals(['playinghooky_ok'], \Civi::$statics[__CLASS__]['doSomethingLog']);
     $this->assertEquals('ok', $result['outcome']);
   }
@@ -357,19 +360,19 @@ public function testRetryWithEventualFailure(string $errorMode) {
       'retry_interval' => 0,
       'lease_time' => 1,
     ]);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
       ['playinghooky']
     ));
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 1, 0, $queue);
 
     $claimAndRun = function($expectOutcome, $expectEndCount) use ($queue, $queueName) {
       $claim = $this->waitForClaim(0.5, 5, $queueName);
-      $this->assertEquals(1, $queue->numberOfItems());
+      $this->assertQueueStats(1, 0, 1, $queue);
       $result = Queue::runItems(0)->setItems([$claim])->execute()->first();
-      $this->assertEquals($expectEndCount, $queue->numberOfItems());
+      $this->assertEquals($expectEndCount, $queue->getStatistic('total'));
       $this->assertEquals($expectOutcome, $result['outcome']);
     };
 
@@ -411,7 +414,7 @@ public function testUserJobQueue_Completion() {
       'runner' => 'task',
       'error' => 'delete',
     ]);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     $userJob = \Civi\Api4\UserJob::create(FALSE)->setValues([
       'job_type:name' => 'contact_import',
@@ -429,20 +432,20 @@ public function testUserJobQueue_Completion() {
     ));
 
     // Verify initial status
-    $this->assertEquals(2, $queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $queue);
     $this->assertEquals(FALSE, isset($firedQueueStatus[$queueName]));
     $this->assertEquals(TRUE, $queue->isActive());
     $this->assertEquals(4, UserJob::get()->addWhere('id', '=', $userJob['id'])->execute()->first()['status_id']);
 
     // OK, let's run both items - and check status afterward.
     Queue::runItems(FALSE)->setQueue($queueName)->execute()->single();
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 1, 0, $queue);
     $this->assertEquals(FALSE, isset($firedQueueStatus[$queueName]));
     $this->assertEquals(TRUE, $queue->isActive());
     $this->assertEquals(4, UserJob::get()->addWhere('id', '=', $userJob['id'])->execute()->first()['status_id']);
 
     Queue::runItems(FALSE)->setQueue($queueName)->execute()->single();
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
     $this->assertEquals('completed', $firedQueueStatus[$queueName]);
     $this->assertEquals(FALSE, $queue->isActive());
     $this->assertEquals(1, UserJob::get()->addWhere('id', '=', $userJob['id'])->execute()->first()['status_id']);
@@ -468,7 +471,7 @@ public function testServiceQueue_NeverComplete() {
       'runner' => 'task',
       'error' => 'delete',
     ]);
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
 
     \Civi::queue($queueName)->createItem(new \CRM_Queue_Task(
       [QueueTest::class, 'doSomething'],
@@ -480,18 +483,18 @@ public function testServiceQueue_NeverComplete() {
     ));
 
     // Verify initial status
-    $this->assertEquals(2, $queue->numberOfItems());
+    $this->assertQueueStats(2, 2, 0, $queue);
     $this->assertEquals(FALSE, isset($firedQueueStatus[$queueName]));
     $this->assertEquals(TRUE, $queue->isActive());
 
     // OK, let's run both items - and check status afterward.
     Queue::runItems(FALSE)->setQueue($queueName)->execute()->single();
-    $this->assertEquals(1, $queue->numberOfItems());
+    $this->assertQueueStats(1, 1, 0, $queue);
     $this->assertEquals(FALSE, isset($firedQueueStatus[$queueName]));
     $this->assertEquals(TRUE, $queue->isActive());
 
     Queue::runItems(FALSE)->setQueue($queueName)->execute()->single();
-    $this->assertEquals(0, $queue->numberOfItems());
+    $this->assertQueueStats(0, 0, 0, $queue);
     $this->assertEquals(FALSE, isset($firedQueueStatus[$queueName]));
     $this->assertEquals(TRUE, $queue->isActive());
   }