minor symfony#25271 [FrameworkBundle] Fix visibility of a test helper (dunglas)

This PR was merged into the 2.7 branch.

Discussion
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[FrameworkBundle] Fix visibility of a test helper

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | no
| New feature?  | no <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md files -->
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Commits
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23b5758 [FrameworkBundle] Fix visibility of a test helper

Author: fabpot

src/Symfony/Bundle/FrameworkBundle/Tests/Controller/RedirectControllerTest.php

@@ -290,7 +290,7 @@ private function createRedirectController($httpPort = null, $httpsPort = null)
         return $controller;
     }
 
-    public function assertRedirectUrl(Response $returnResponse, $expectedUrl)
+    private function assertRedirectUrl(Response $returnResponse, $expectedUrl)
     {
         $this->assertTrue($returnResponse->isRedirect($expectedUrl), "Expected: $expectedUrl\nGot:      ".$returnResponse->headers->get('Location'));
     }