fix test for email pattern

extension/Tests/unit/core/BuildFormPlainTest.php

@@ -152,7 +152,7 @@ class BuildFormPlainTest extends AbstractDatabaseTest {
         $formElement[FE_CHECK_TYPE] = SANITIZE_ALLOW_EMAIL;
         $formElement[FE_CHECK_PATTERN] = '';
         $result = $build->buildInput($formElement, 'name:1', '', $json);
-        $label['123'][API_ELEMENT_ATTRIBUTE]['pattern'] = '^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$';
+        $label['123'][API_ELEMENT_ATTRIBUTE]['pattern'] = '^([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,})?$';
         $this->assertEquals('<input id="123" name="name:1" class="form-control" maxlength="255" type="input" value="" pattern="^([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,})?$" data-pattern-error="' . SANITIZE_ALLOW_EMAIL_MESSAGE . '" data-error="Error" data-hidden="no" data-required="no" ><div class="help-block with-errors hidden"></div>', $result);
         $this->assertEquals(['disabled' => false, FE_MODE_REQUIRED => '', 'form-element' => 'name:1', 'value' => '', API_ELEMENT_UPDATE => $label], $json);