Here’s a minimal example of a C++ unit test program using Google Test. You can copy the sample code by choosing the Help -> Using Google Test… menu entry.
A Google Test based unit test needs #include <gtest/gtest-gui.h> in place of the regular gtest.h header file to support BoostTestUi. The gtest-gui.h file can be created from the File -> Create Header -> Google Test… menu. Save the header file somewhere in a gtest subfolder in your include path, typically inside the gtest folder itself.
BoostTestUi will detect a Google Test executable without the special #include file and show you a reminder.