First try of fixing tests

I think this should help you fixing the tests...there must be something wrong with the parameters but I can't figure it out right now.
What about changing this to:

```php
$fileMock->expects($this->any())->method('__get')->will($this->returnCallback(
    function($key) use($arguments) {
        ...
    }
));
```

and remove `currentProviderData` and `getMagicGetterValueTestComputeResizeWithoutImportantPart`?