MAGETWO-90719: Exception is thrown when you re-order a product with custom options from Admin.

- Fix integration test to cover changes in Zend framework

Author: admanesachin

dev/tests/integration/testsuite/Magento/Catalog/Model/Product/Option/Type/File/ValidatorInfoTest.php

@@ -111,11 +111,11 @@ public function testExceptionWithoutErrors()
      */
     public function testValidate()
     {
-        $validateMock = $this->createPartialMock(\Zend_Validate::class, ['isValid']);
-        $validateMock->expects($this->once())->method('isValid')->will($this->returnValue(true));
+        //use actual zend class to test changed functionality
+        $validate = $this->objectManager->create(\Zend_Validate::class );
         $this->validateFactoryMock->expects($this->once())
             ->method('create')
-            ->will($this->returnValue($validateMock));
+            ->will($this->returnValue($validate));
         $this->assertTrue(
             $this->model->validate(
                 $this->getOptionValue(),