Pre-installation checks

[imobachgs]

Problem

D-Installer does not perform any pre-installation check. So if you click the "Install" button, it will blindly try to install the system. It does not matter whether you have provided all the required information.

See #285 or #177 as examples.

Solution

This is the first version of a mechanism to report the issues that might block the installation. We might add some additional information to these validation errors in the future (severity, scope, etc.), but we need to start with something simple enough.

The implementation has two parts:

• A new org.opensuse.DInstaller.Validation1 that exposes the validation errors. The D-Bus layer takes care of keeping this information in sync, so the only thing that the backend classes need to provide is a #validate method (like Manager#validate or Users#validate).
• Support at UI level to display these validation errors:
  • In the users section, the errors are shown after the user clicks the Install button.
  • In storage, the errors are always visible.

Demo

User and storage checks

demo-d-installer-checks.webm

Multiple errors

When there are multiple errors, they are shown in a pop-over. Of course, in the example below, the second is a testing error. Bear in mind that, by now, this situation should not happen.

TODO

• Improve how errors are presented
• Document the Validation1 interface
• Extract the InstallButton component to a separate file
• Fix unit tests
• Rename IsValid to just Valid.

[coveralls]

Coverage increased (+0.07%) to 74.747% when pulling 93b99e8 on pre-install-checks into 1e3f516 on master.

[joseivanlopez]

Only minor things. For the UI part ... I did my best to understand it :), but it looks ok. Great work!

[joseivanlopez]

LGTM