diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleExportTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleExportTest.php
index 673867f..a933f8b 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleExportTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleExportTest.php
@@ -39,6 +39,14 @@ class LocaleExportTest extends WebTestBase {
 
     $this->admin_user = $this->drupalCreateUser(array('administer languages', 'translate interface', 'access administration pages'));
     $this->drupalLogin($this->admin_user);
+
+    // Set the translation file directory to something writable.
+    $destination = conf_path() . '/files/translations';
+    file_prepare_directory($destination, FILE_CREATE_DIRECTORY);
+
+    // Copy test po files to the same directory.
+    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.de.po', $destination, FILE_EXISTS_REPLACE);
+    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.xx.po', $destination, FILE_EXISTS_REPLACE);
   }
 
   /**
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleFileImportStatus.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleFileImportStatus.php
index b023335..53cadc0 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleFileImportStatus.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleFileImportStatus.php
@@ -40,8 +40,8 @@ class LocaleFileImportStatus extends WebTestBase {
     file_prepare_directory($destination, FILE_CREATE_DIRECTORY);
 
     // Copy test po files to the same directory.
-    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.de.po', $destination, FILE_EXISTS_ERROR);
-    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.xx.po', $destination, FILE_EXISTS_ERROR);
+    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.de.po', $destination, FILE_EXISTS_REPLACE);
+    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.xx.po', $destination, FILE_EXISTS_REPLACE);
   }
 
   /**
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
index f5f2501..8d847ae 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
@@ -41,8 +41,8 @@ class LocaleImportFunctionalTest extends WebTestBase {
     file_prepare_directory($destination, FILE_CREATE_DIRECTORY);
 
     // Copy test po files to the same directory.
-    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.de.po', $destination, FILE_EXISTS_ERROR);
-    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.xx.po', $destination, FILE_EXISTS_ERROR);
+    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.de.po', $destination, FILE_EXISTS_REPLACE);
+    file_unmanaged_copy(drupal_get_path('module', 'locale') . '/tests/test.xx.po', $destination, FILE_EXISTS_REPLACE);
 
     $this->admin_user = $this->drupalCreateUser(array('administer languages', 'translate interface', 'access administration pages'));
     $this->drupalLogin($this->admin_user);