Do not set your self up to fail a 135 Checkride! That will be with you where ever you go. The operator has not provided sufficient time for indoc, ground school and flight training under ANY companies' new hire and initial aircraft training program. Previous 135 or in an similar aircraft is a different story. If the employer has painted themself into a corner and expecting you to adapt, they are representing their (un)professionalism to their POI who is likely well aware of the practices of the operator already. I have know of POI's who otherwise were really great guys capturing an opportunity like this to send a message to the Operator by thoroughly examining the newhire's rectum and documenting every deficiency. Unfortunately, the candidate becomes a casualty in this exercise.
If you are checked out with a company check airman with a rubber stamp, I agree partly with what a previous poster has implied. If in fact the checkride is with the POI, you will likely be alone and conduct a records and log review prior to beginning the Oral portion of the checkride. Voice your concerns then and at ANY time you begin to feel uncomfortable or unprepared with the material being evaluated. It is at the POI's discretion to file paperwork that will go into your record for an UNSAT during the Oral. Once in the Cockpit, that UNSAT paperwork is required except under certain conditions which will be explained to you. Again, if you are uncomfortable with the maneuvers or exercise at any time, you have the right to discontinue the examination and return to the airport. The flight is required to be rescheduled and no determination of your performance is allowed. Previous (poor) performance is not supposed to be used during the subsequent flight evaluation. It is purposed as a fresh start completely. Of course, at their discretion, the examiner may use the successful portions of the previous flight, however, will definately require the portions where you were deficient before. You and the examiner each reserve the right to discontinue the flight for any reason and at any time.
This operator is conducting business in a very shady area of the FAR's. They are more than likely cutting corners in other areas to turn a profit as well. Performance like this is why so many of us legit business are so heavily scrutinized, financially, operationally and professionally. These occurances are becoming more frequent and that is a shame. If you bag on the gig, there are likely 10 others salivating behind you eager to step in and probably with less impressive credentials. I would await a better opportunity if you could and have others in the stew.
I would strongly recommend that if the checkride is internal, become an expert in the regs and aircraft. Failure to do so will increase the chances down the road of certificate action stemming from any number of possibilities to which ignorance is not a defense as per many Far's in 61, 91, 119 and 135. And I certaintly don't want to read about you in the not-so-funny papers come winter. Get sharp and stay that way always (sooner rather than later) looking for the next better job. The barron is a great pleasure to fly but it can eat your lunch if this is your first exposure to high(er) performance twins. Many instrument panels, radio stacks and throttle quadrants are non-standard. A majority have the Gear and Flap controls in reverse locations which has led to a number of gear "collapses".
Good luck.
100-1/2
p.s. - Hey, Tony! What happened to your avatar?