[Form] Fix forward compat of AbstractLayoutTest

Author: nicolas-grekas

Tests/AbstractLayoutTest.php

@@ -2422,7 +2422,11 @@ public function testWidgetAttributes()
         $html = $this->renderWidget($form->createView());
 
         // compare plain HTML to check the whitespace
-        $this->assertSame('<input type="text" id="text" name="text" readonly="readonly" disabled="disabled" required="required" maxlength="10" pattern="\d+" class="foobar" data-foo="bar" value="value" />', $html);
+        try {
+            $this->assertSame('<input type="text" id="text" name="text" readonly="readonly" disabled="disabled" required="required" maxlength="10" pattern="\d+" class="foobar" data-foo="bar" value="value" />', $html);
+        } catch (\PHPUnit_Framework_AssertionFailedError $e) {
+            $this->assertSame('<input type="text" id="text" name="text" disabled="disabled" required="required" readonly="readonly" maxlength="10" pattern="\d+" class="foobar" data-foo="bar" value="value" />', $html);
+        }
     }
 
     public function testWidgetAttributeNameRepeatedIfTrue()