Hello Lukasz,
Looking at your net.smartam.leeloo.integration.Common file, I can see that in your integration tests you always set a Content-Type header:
c.setRequestProperty("Content-Type", OAuth.ContentType.URL_ENCODED);
A normal web browser doing a GET request will not set this content type.
If I remove this line, then one of your tests will actually fail.
Could you maybe comment on this? It may explain the problem I'm having in my own code.
Markus