diff --git a/modules/simpletest/tests/cache.test b/modules/simpletest/tests/cache.test
index b42de360b4..70efc396f1 100644
--- a/modules/simpletest/tests/cache.test
+++ b/modules/simpletest/tests/cache.test
@@ -198,6 +198,19 @@ class CacheGetMultipleUnitTest extends CacheTestCase {
     $this->assertTrue($this->checkCacheExists('item1', $item1), 'Item 1 is cached.');
     $this->assertTrue($this->checkCacheExists('item2', $item2), 'Item 2 is cached.');
 
+    // Ensure variable_set refreshes stale cache.
+    $case_no = variable_get('mytest_next_case', 10001); // Expected 10001.
+    variable_set('mytest_next_case', $case_no + 1); // Sets to 10002.
+    $case_no_2 = variable_get('mytest_next_case'); // Expected 10002.
+    variable_set('mytest_next_case', $case_no + 1); // Sets to 10003.
+    $case_no_3 = variable_get('mytest_next_case'); // Expected 10003.
+    $this->assertEqual($case_no_2, 10002, 'Expected value was returned from cache successfully.');
+    variable_set('mytest_next_case', $case_no + 1); // Sets to 10004.
+    $this->assertEqual($case_no_3, 10003, 'Expected value was returned from cache successfully.');
+    $case_no_4 = variable_get('mytest_next_case'); // Expected 10004.
+    $this->assertEqual($case_no_4, 10004, 'Expected value was returned from cache successfully.');
+    // End ensure variable_set refreshes stale cache.
+
     // Fetch both records from the database with cache_get_multiple().
     $item_ids = array('item1', 'item2');
     $items = cache_get_multiple($item_ids, $this->default_bin);