Integration

In the last week we had problems with the integration of the keyboard but Sergio Collazon and Cecilia worked in the problem and finished. Without controlling integration developers test their code and integrate believing all is well. But because of parallel integration there is a combination of source code which has not been tested together before. Integration problems happen without detection.
Further problems happen when there is no clear cut latest version. This applies not only to the source code but the unit test suite which must verify the source code correctness. If you can not lay your hands on a complete, correct, and consistent test suite you will be chasing bugs that do not exist and passing up bugs that do.
You can have developers own specific classes. Class owners integrate and commit to the repository properly. Interclass dependencies can still be wrong. Class owners can become bottle necks if one class requires many changes and it doesn't solve the whole problem.
Yet another way is to appoint an integrator or integration team. Integrating code from multiple developers is more than a single person can handle.