Adaptations needed for a richer DBus interface

[ancorgs]

Problem

To implement the storage management we envision for the D-Installer we need the ability to run the GuidedProposal with a couple of customizations:

• Trying only once with one of the target sizes (we don't want the double attempt with desired and min in D-Installer because it can be confusing).
• Having the possibility to force the min and max sizes of all volumes, disabling the mechanisms that adjust them (like the modifier related to activating snapshots)

Solution

Implemented a new subclass MinGuidedProposal that tries only once using the min_size as starting point and ignoring the desired_size. Surely inheritance is not the nicest mechanism but it works perfectly here and is the mechanism that was chosen to customize the GuidedProposal (eg. InitialGuidedProposal).

Added two new flags to VolumeSpecification to ignore the automatic size adjustments.

Added the possibility to store a failed proposal in the StorageManager. That makes no sense in the context of YaST but is used in D-Installer (since the proposal is the only mechanism there to produce an staging devicegraph).

Testing

Added unit tests for the new functionality

[coveralls]

Coverage increased (+0.002%) to 97.809% when pulling eed719e3065ff1817c594d3078f7de32998b2793 on ancorgs:dbus_volumes into ae78d399c9279756cbbf540fe86acd2b8292d773 on yast:master.

[yast-bot]

:heavy_check_mark: Public Jenkins job #446 successfully finished :heavy_check_mark: Created OBS submit request #1035071

[yast-bot]

:heavy_check_mark: Internal Jenkins job #1132 successfully finished :heavy_check_mark: Created IBS submit request #284313