public function testExportVarnishConfigAction()
{
$fileContent = 'some conetnt';
$filename = 'varnish.vcl';
$responseMock = $this->getMockBuilder('Magento\\Framework\\App\\ResponseInterface')->disableOriginalConstructor()->getMock();
$this->configMock->expects($this->once())->method('getVclFile')->will($this->returnValue($fileContent));
$this->fileFactoryMock->expects($this->once())->method('create')->with($this->equalTo($filename), $this->equalTo($fileContent), $this->equalTo(DirectoryList::VAR_DIR))->will($this->returnValue($responseMock));
$result = $this->action->executeInternal();
$this->assertInstanceOf('Magento\\Framework\\App\\ResponseInterface', $result);
}
