When an issue has been identified that is specific to the Mac, TransGaming's R&D team becomes responsible for tracking things down and fixing the problem. This is no easy task, and requires developers who have broad knowledge of Windows and MacOS, DirectX and OpenGL, and who really really enjoy debugging complex problems - if you think that describes you, please let us know! 8-). Every change that the R&D team does to the core code for Cider is rigorously examined with a two-level code review process, one review by peers on the team, and another by a lead developer who is intimately familiar with the code in question.
In some cases, the problem turns out to be not within Cider, but with code at the Operating System or driver layer. At that point, we file bug reports with Apple's 'Radar' system, and try to provide as much information as possible to them so that they can reproduce a bug. To help with this process, we often use an internal tool which we call 'Snap', which records all D3D graphics commands used within a frame of a game into a file that can be played back later, separately from the game itself. This is especially useful for us when complicated steps are required to get to a point in the game where the problem occurs, so that the driver developers don't have to actually play things through to reproduce a bug!