Why doesn't this mock the logging call?

So I am not sure what I am doing wrong but:

class Details {

    public function details($href) {
        $client = new Client();
        $eveLog = new EveLogHandler();

        $response = $client->request('GET', $href);
        $eveLog->requestLog($response, 'eveonline_item_details.log');

        if ($response->getStatusCode() === 200) {
            return json_decode($response->getBody()->getContents());
        }

        return false;
    }
}

I want to mock this: $eveLog->requestLog($response, 'eveonline_item_details.log');

So I wrote a test:

class DetailsTest extends \PHPUnit_Framework_TestCase {

    public function getLogMock() {
        return $this->getMockBuilder('EveOnline\Logging\EveLogHandler')
             ->setMethods(['requestLog'])
             ->getMock();
    }

    public function testDetailsDoesNotReturnFalse() {

        $details = new EveOnline\Items\Details();

        $logger = $this->getLogMock();
        $logger->expects($this->exactly(1))
            ->method('requestLog')
            ->with('request', 'request.log');

        $response = $details->details('http://example.com');

        $this->assertNotFalse($response);
    }
}

Accept it doesnt mock the method call, instead it freaks out with an error:

1) DetailsTest::testDetailsDoesNotReturnFalse
Error: Call to undefined function EveOnline\Logging\storage_path()

Now this method: storage_path is a laravel method and since this library is out side of laravel, for development purposes, the method doesn't exist, hence me trying to mock the call to: $eveLog->requestLog($response, 'eveonline_item_details.log');

Two questions arise from this:

1. First of all why doesn't my test pick up on the fact that I have mocked the method call?
2. When it coms time to test this particular method how do you mock global functions? Laravel has a few of them and I'll need mock out the storage_path method.

Ideas?