N°2651 rollback gitignore for lib tests dirs

Too dangerous ! We'll work properly on this but for 2.8

lib/symfony/http-kernel/Tests/Exception/ServiceUnavailableHttpExceptionTest.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Symfony\Component\HttpKernel\Tests\Exception;
+
+use Symfony\Component\HttpKernel\Exception\ServiceUnavailableHttpException;
+
+class ServiceUnavailableHttpExceptionTest extends HttpExceptionTest
+{
+    public function testHeadersDefaultRetryAfter()
+    {
+        $exception = new ServiceUnavailableHttpException(10);
+        $this->assertSame(['Retry-After' => 10], $exception->getHeaders());
+    }
+
+    /**
+     * @dataProvider headerDataProvider
+     */
+    public function testHeadersSetter($headers)
+    {
+        $exception = new ServiceUnavailableHttpException(10);
+        $exception->setHeaders($headers);
+        $this->assertSame($headers, $exception->getHeaders());
+    }
+
+    protected function createException()
+    {
+        return new ServiceUnavailableHttpException();
+    }
+}