Full support for Core and GUI elements destruction

[franzlst]

In the branch: full_destruct the implementation of a destruction test for all RAFCON objects is insert. The issue concerns sub-tasks to let this test succeed with all asserts enabled. The first object destruction test with core elements only are already working. The test with core-elements and respective models only shows that the core elements successfully destruct with implementation of weak references between model and respective core element. This result into failures in other tests and is the reason to develop this GUI enhancement in a separate branch.

A object destruction is verified when the garbage collector has called the del method of respective object.

The sub-task of this issue are:

• fully verified core object destruction while running test method test_core_destruct in test_destruct-module
  • all core objects
• fully verified core + model object destruction test while running test method test_model_and_core_destruct in test_destruct-module
  • all core objects
  • all model objects
• fully verified core + model + extended controller object destruction while running test method test_model_and_core_destruct_with_gui in test_destruct-module
  • all core objects
  • all model objects
  • all extended controller objects
• full core + model + gtkmvc view and controller object destruction while running test method test_widget_destruct in test_destruct-module
  • all core objects
  • all model objects
  • all extended controller objects
  • all gtkmvc.View objects
  • all gtkmvc.Controller objects
  • maybe verified gtk.View object destruction (used in graphical editor) if needed

Some of the sub-task maybe change if the test is generalized, again, e.g. to increase coverage of RAFCON Core or GUI elements.

Originally created by @Rbelder at 2016-11-28 17:00:23+00:00 (moved from RMC internal repository)