minor symfony#10483 [2.3][Process] Fix unit tests in sigchild disabled environment (romainneutron)

This PR was merged into the 2.3 branch.

Discussion
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[2.3][Process] Fix unit tests in sigchild disabled environment

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

We've been a bit fast when merging symfony#10480 and tests were broken in the last update I did.

Commits
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5f6ee12 [Process] Fix unit tests in sigchild disabled environment

Author: fabpot

src/Symfony/Component/Process/Tests/SigchildDisabledProcessTest.php

@@ -133,6 +133,15 @@ public function testExitCodeText()
         $process->getExitCodeText();
     }
 
+    /**
+     * @expectedException \Symfony\Component\Process\Exception\RuntimeException
+     * @expectedExceptionMessage This PHP has been compiled with --enable-sigchild. You must use setEnhanceSigchildCompatibility() to use this method.
+     */
+    public function testExitCodeTextIsNullWhenExitCodeIsNull()
+    {
+        parent::testExitCodeTextIsNullWhenExitCodeIsNull();
+    }
+
     /**
      * @expectedException \Symfony\Component\Process\Exception\RuntimeException
      * @expectedExceptionMessage This PHP has been compiled with --enable-sigchild. You must use setEnhanceSigchildCompatibility() to use this method.