Fix the cleanup function and extend the test to `dict` and `list`
proprties. Also migrate to `pytest` fixtures and exception handling.

- Use all `DataHandle` members in the comparison operator.
- Add `path` accessor for consistency with other members.
- Make the class non-hashable also in Python2 (this is the default
  behavior in Python3).
- Split DataHandle-specific unit tests into their own file and improve
  coverage.

- add support for `isCondition` flag
- add mode, type and isCondition values to option representation
- make `setstate`/`getstate` generic
- improve unit test coverage

Move the property declaration of data handles one level lower in the
inheritance hierarchy, i.e. from `DataObjectHandleBase` to `DataHandle`. The
only user-visible change should be the change in type of the python
configurable class from `DataObjectHandleBase` to `DataHandle`. This change
will allow other types of handles (e.g. in ATLAS) to profit from the
python type information.

The forward compatible syntax from 2.6 plus is:

    except SomeException as err

rather than

    except SomeException, err

Gitlab CI authored 6 years ago and Marco Clemencic committed 6 years ago

patch generated by standalone job

This helps the transition to data handles whenever we have the pattern
`B.Input = A.Output` and `A.Output` is changed to a data handle and `B.Input`
is still a string.

Fixes gaudi/Gaudi#22