warpExposure and warpImage are supposed to throw an exception if destImage = srcImage. However, the unit test for this is mis-written, due to checking for Exception being raised, instead of a more specific exception, hiding other problems. The test case in question is testWarpIntoSelf.
Worse, on my Mac, when I correct the test I find that it is possible to warp one image or exposure into itself, even though this results in altering the supposedly const input image and produces an incorrect destination image. Thus the C++ code that attempts to check for dest == src is not working.