OrbisCAD and GDBMS have over 200 unit tests and that number keeps growing as the functionalities are developed, so we can proudly say that enough reliability is guaranteed.
Nevertheless, the project is built on top of several open source projects. Some of them are currently being developed (gvSIG, GDBMS), but they are also being widely and actively used (GDBMS is also used by gvSIG, for instance), so any bug can be quickly fixed. The remaining libraries have been used for a long time and have a proved reliability: OrbisCAD uses the fastest gvSIG drawing system, the data access framework GDBMS and the topology in JTS.