diff --git a/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php b/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php
index 2ebcbbad7607f625ae341e80363a7edfde664729..51cdcda65ffce53b3d3e5db69ba846b99179b6df 100644
--- a/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php
+++ b/core/modules/migrate/src/Plugin/migrate/source/SourcePluginBase.php
@@ -423,7 +423,7 @@ public function count($refresh = FALSE) {
     // class to get the count from the source.
     if ($refresh || !$this->cacheCounts) {
       $count = $this->getIterator()->count();
-      $this->getCache()->set($this->cacheKey, $count, 'cache');
+      $this->getCache()->set($this->cacheKey, $count);
     }
     else {
       // Caching is in play, first try to retrieve a cached count.
@@ -436,7 +436,7 @@ public function count($refresh = FALSE) {
         // No cached count, ask the derived class to count 'em up, and cache
         // the result.
         $count = $this->getIterator()->count();
-        $this->getCache()->set($this->cacheKey, $count, 'cache');
+        $this->getCache()->set($this->cacheKey, $count);
       }
     }
     return $count;
diff --git a/core/modules/migrate/tests/src/Unit/MigrateSourceTest.php b/core/modules/migrate/tests/src/Unit/MigrateSourceTest.php
index d6e726a8c8c0f97c5a5316111431d741a1cfeb68..72d7b49deeeba80734fae8c42401a3dfa0a59f7e 100644
--- a/core/modules/migrate/tests/src/Unit/MigrateSourceTest.php
+++ b/core/modules/migrate/tests/src/Unit/MigrateSourceTest.php
@@ -139,10 +139,12 @@ public function testHighwaterTrackChangesIncompatible() {
    * Test that the source count is correct.
    */
   public function testCount() {
-
+    // Use the Apcu cache backend, which confirms that the cache API is being
+    // properly used.
     $container = new ContainerBuilder();
-    $container->register('cache.migrate', 'Drupal\Core\Cache\NullBackend')
-      ->setArguments(['migrate']);
+    $cache_tags_checksum = $this->getMock('\Drupal\Core\Cache\CacheTagsChecksumInterface');
+    $container->register('cache.migrate', 'Drupal\Core\Cache\ApcuBackend')
+      ->setArguments(['migrate', 'migrate', $cache_tags_checksum]);
     \Drupal::setContainer($container);
 
     // Test that the basic count works.