Use alternative theme for testing as `P2` theme has been retired

[ernilambar]

Bug Report

• Yes, I reviewed the contribution guidelines.
• Yes, more specifically, I reviewed the guidelines on how to write clear bug reports.

Describe the current, buggy behavior

P2 theme has been removed from the directory. Ref: https://themes.trac.wordpress.org/ticket/30322

We need to find more reliable alternative theme for feature tests.

Reference of P2 theme in our tests: https://github.com/search?q=org%3Awp-cli%20%22wp%20theme%20install%20p2%22&type=code

[tfirdaus]

@ernilambar the default theme could be a good replacement in this case :). I think it's been one of the most iconic theme in WordPress.

[ernilambar]

@tfirdaus Since we have already used TwentyTwelve in several tests, may be it would be good replacement. I have updated feature test in widget command here. wp-cli/widget-command#61

[tfirdaus]

@ernilambar I have it updated in the extension command wp-cli/extension-command#417

[tfirdaus]

@ernilambar I got a problem in wp-cli/extension-command#417 though, where it says the theme is already installed.

005 Scenario: Attempting to delete a theme that doesn't exist # features/theme-delete.feature:110
      And I run `wp theme install twentytwelve`               # features/theme-delete.feature:5
        $ wp theme install twentytwelve
        Success: Theme already installed.

What would be the better approach here:

• Should I pick other theme just for this case?
• Or, should we find an alternative that might work for all theme install scenario in the feature tests?

[ernilambar]

Done

• Update the theme in feature tests extension-command#417
• Update theme tests to remove P2 and use TwentyTwelve scaffold-command#336
• Use TwentyTwelve theme in menu location test entity-command#494