diff --git a/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/DatabaseStorageExpirableTest.php b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/DatabaseStorageExpirableTest.php
index 7b592be..b173445 100644
--- a/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/DatabaseStorageExpirableTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/KeyValueStore/DatabaseStorageExpirableTest.php
@@ -44,21 +44,20 @@ protected function tearDown() {
    */
   public function testCRUDWithExpiration() {
     // Verify that an item can be stored with setWithExpire().
-    $expire = 604800;
-    $this->verbose($expire);
-    $this->store1->setWithExpire('foo', $this->objects[0], $expire);
+    // Use a random expiration in each test.
+    $this->store1->setWithExpire('foo', $this->objects[0], rand(500, 299792458));
     $this->assertIdenticalObject($this->objects[0], $this->store1->get('foo'));
     // Verify that the other collection is not affected.
     $this->assertFalse($this->store2->get('foo'));
 
     // Verify that an item can be updated with setWithExpire().
-    $this->store1->setWithExpire('foo', $this->objects[1], $expire);
+    $this->store1->setWithExpire('foo', $this->objects[1], rand(500, 299792458));
     $this->assertIdenticalObject($this->objects[1], $this->store1->get('foo'));
     // Verify that the other collection is still not affected.
     $this->assertFalse($this->store2->get('foo'));
 
     // Verify that the expirable data key is unique.
-    $this->store2->setWithExpire('foo', $this->objects[2], $expire);
+    $this->store2->setWithExpire('foo', $this->objects[2], rand(500, 299792458));
     $this->assertIdenticalObject($this->objects[1], $this->store1->get('foo'));
     $this->assertIdenticalObject($this->objects[2], $this->store2->get('foo'));
 
@@ -67,7 +66,7 @@ public function testCRUDWithExpiration() {
       'foo' => $this->objects[3],
       'bar' => $this->objects[4],
     );
-    $this->store1->setMultipleWithExpire($values, $expire);
+    $this->store1->setMultipleWithExpire($values, rand(500, 299792458));
     $result = $this->store1->getMultiple(array('foo', 'bar'));
     foreach ($values as $j => $value) {
       $this->assertIdenticalObject($value, $result[$j]);
@@ -101,9 +100,9 @@ public function testCRUDWithExpiration() {
     // Test that setWithExpireIfNotExists() succeeds only the first time.
     $key = $this->randomName();
     for ($i = 0; $i <= 1; $i++) {
-      // setIfNotExists() should be TRUE the first time (when $i is 0) and
-      // FALSE the second time (when $i is 1).
-      $this->assertEqual(!$i, $this->store1->setWithExpireIfNotExists($key, $this->objects[$i], $expire));
+      // setWithExpireIfNotExists() should be TRUE the first time (when $i is
+      // 0) and FALSE the second time (when $i is 1).
+      $this->assertEqual(!$i, $this->store1->setWithExpireIfNotExists($key, $this->objects[$i], rand(500, 299792458)));
       $this->assertIdenticalObject($this->objects[0], $this->store1->get($key));
       // Verify that the other collection is not affected.
       $this->assertFalse($this->store2->get($key));
@@ -111,7 +110,7 @@ public function testCRUDWithExpiration() {
 
     // Remove the item and try to set it again.
     $this->store1->delete($key);
-    $this->store1->setIfNotExists($key, $this->objects[1]);
+    $this->store1->setWithExpireIfNotExists($key, $this->objects[1], rand(500, 299792458));
     // This time it should succeed.
     $this->assertIdenticalObject($this->objects[1], $this->store1->get($key));
     // Verify that the other collection is still not affected.
diff --git a/core/modules/user/lib/Drupal/user/TempStore.php b/core/modules/user/lib/Drupal/user/TempStore.php
index 9ebde36..c8a6dd1 100644
--- a/core/modules/user/lib/Drupal/user/TempStore.php
+++ b/core/modules/user/lib/Drupal/user/TempStore.php
@@ -23,8 +23,8 @@
  * elsewhere, e.g. autosave data, multistep forms, or in-progress changes
  * to complex configuration that are not ready to be saved.
  *
- * Each TempStore belongs belongs to a particular owner (e.g. a user, session,
- * or process). Multiple owners may use the same key/value collection, and the
+ * Each TempStore belongs to a particular owner (e.g. a user, session, or
+ * process). Multiple owners may use the same key/value collection, and the
  * owner is stored along with the key/value pair.
  *
  * Every key is unique within the collection, so the TempStore can check
diff --git a/core/modules/user/lib/Drupal/user/Tests/TempStoreDatabaseTest.php b/core/modules/user/lib/Drupal/user/Tests/TempStoreDatabaseTest.php
index b0ef393..362e739 100644
--- a/core/modules/user/lib/Drupal/user/Tests/TempStoreDatabaseTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/TempStoreDatabaseTest.php
@@ -94,7 +94,8 @@ public function testUserTempStore() {
     $key = $this->randomName();
     // Test that setIfNotExists() succeeds only the first time.
     for ($i = 0; $i <= 1; $i++) {
-      // setIfNotExists() should fail the second time ($i = 1).
+      // setIfNotExists() should be TRUE the first time (when $i is 0) and
+      // FALSE the second time (when $i is 1).
       $this->assertEqual(!$i, $this->stores[0]->setIfNotExists($key, $this->objects[$i]));
       $metadata = $this->stores[0]->getMetadata($key);
       $this->assertEqual($this->users[0], $metadata->owner);