I have a C++Builder 2010 project and want to add tests to it. So, instead of pausing the output of my console window to read the outcome of the tests, I want to print the same information to the Output Window in C++Builder (not in the Event Log).
So OutputDebugString is not an option for me. Is there some specific way to either redirect console output to the Output Window or to print directly there?

You can simply define a Post-build event in your Project Options to run your executable. Its console output will automatically be included in Output messages.