minor #14632 [HttpFoundation] Fix volatile MongoDbSessionHandlerTest::testRead() (nicolas-grekas)

This PR was merged into the 2.3 branch.

Discussion
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[HttpFoundation] Fix volatile MongoDbSessionHandlerTest::testRead()

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Commits
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57571a9 [HttpFoundation] Fix volatile MongoDbSessionHandlerTest::testRead()

src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MongoDbSessionHandlerTest.php

@@ -87,7 +87,7 @@ class MongoDbSessionHandlerTest extends \PHPUnit_Framework_TestCase
 
         // defining the timeout before the actual method call
         // allows to test for "greater than" values in the $criteria
-        $testTimeout = time();
+        $testTimeout = time() + 1;
 
         $collection->expects($this->once())
             ->method('findOne')