diff -u b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
--- b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
@@ -869,7 +869,7 @@
    * Creates simpletest_settings.php file.
    *
    * @param array $conf
-   *   Conf overrides to add to the simpletest_settings.php, for eaxmple:
+   *   Conf overrides to add to the simpletest_settings.php, for example:
    *   @code
    *     array(
    *       'page_cache_without_database' = TRUE,
diff -u b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
--- b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
@@ -129,7 +129,7 @@
     $this->createSimpletestSettingsFile($conf);
     $this->drupalGet('');
     $this->assertText('Page returned by Drupal\bootstrap_test\Cache\TestBackend');
-    // Have to clean up settings file so that is does not affect other tests
+    // Clean up settings file so that is does not affect other tests.
     $this->deleteSimpletestSettingsFile();
   }