public function automaticHeadersAreSetOnEachRequest()
{
$requestEngine = $this->createMock(Client\RequestEngineInterface::class);
$requestEngine->expects($this->any())->method('sendRequest')->will($this->returnValue(new Http\Response()));
$this->browser->setRequestEngine($requestEngine);
$this->browser->addAutomaticRequestHeader('X-Test-Header', 'Acme');
$this->browser->addAutomaticRequestHeader('Content-Type', 'text/plain');
$this->browser->request('http://localhost/foo');
$this->assertTrue($this->browser->getLastRequest()->hasHeader('X-Test-Header'));
$this->assertSame('Acme', $this->browser->getLastRequest()->getHeader('X-Test-Header'));
$this->assertContains('text/plain', $this->browser->getLastRequest()->getHeader('Content-Type'));
}