Currently I am in a non-remunerated internship in a company and I'm going to finish it in about 1 month. I was told by my tutor that there's a big chance for them to hire me, the usual contract duration is 1 year but the salary for the first 6 months is a little less than the last 6 months(they do this to test new employees). Also, although the company has a lot of employees (around 200), it's like a startup in terms of organization, so I think I could discuss it with HR and the CEO.
So my question is, since I've been working for 3 months for free, should I negotiate the "test salary" duration? And if so, how should I approach the negotiation?