Merge pull request #3423

0205abd Improve unit test code not to compare with explanatory messages for each platform. Instead, use have an exception object to check if the string returned by what() on the raised exception matches the string returned by what() on the expected exception instance. This way, we do not need to list all different possible explanatory strings for different platforms in the test code, and make it simple. (The idea is by Cory Fields.) (Kangmo)