minor symfony#21180 [PhpUnitBridge] silence warnings on PHPUnit 4.8 (xabbuh)

This PR was merged into the 3.3-dev branch.

Discussion
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[PhpUnitBridge] silence warnings on PHPUnit 4.8

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

The concept of warnings is only available since PHPUnit 5. We can later think about whether we need this for PHPUnit 4.8 to or if we should rather aim to drop PHPUnit 4.8 support in 4.0. For now, this change will make the test suite green again.

Commits
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2c3de10 silence warnings on PHPUnit 4.8

Author: nicolas-grekas

src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php

@@ -212,11 +212,19 @@ public function endTest(\PHPUnit_Framework_Test $test, $time)
         }
 
         if ($test instanceof \PHPUnit_Framework_TestCase && 0 === strpos($test->getName(), 'testLegacy') && !isset($this->testsWithWarnings[$test->getName()]) && !in_array('legacy', $groups, true)) {
-            $test->getTestResultObject()->addWarning($test, new \PHPUnit_Framework_Warning('Using the "testLegacy" prefix to mark tests as legacy is deprecated since version 3.3 and will be removed in 4.0. Use the "@group legacy" notation instead to add the test to the legacy group.'), $time);
+            $result = $test->getTestResultObject();
+
+            if (method_exists($result, 'addWarning')) {
+                $result->addWarning($test, new \PHPUnit_Framework_Warning('Using the "testLegacy" prefix to mark tests as legacy is deprecated since version 3.3 and will be removed in 4.0. Use the "@group legacy" notation instead to add the test to the legacy group.'), $time);
+            }
         }
 
         if ($test instanceof \PHPUnit_Framework_TestCase && strpos($className, '\Legacy') && !isset($this->testsWithWarnings[$test->getName()]) && !in_array('legacy', $classGroups, true)) {
-            $test->getTestResultObject()->addWarning($test, new \PHPUnit_Framework_Warning('Using the "Legacy" prefix to mark all tests of a class as legacy is deprecated since version 3.3 and will be removed in 4.0. Use the "@group legacy" notation instead to add the test to the legacy group.'), $time);
+            $result = $test->getTestResultObject();
+
+            if (method_exists($result, 'addWarning')) {
+                $result->addWarning($test, new \PHPUnit_Framework_Warning('Using the "Legacy" prefix to mark all tests of a class as legacy is deprecated since version 3.3 and will be removed in 4.0. Use the "@group legacy" notation instead to add the test to the legacy group.'), $time);
+            }
         }
     }