User:DWalden (WMF)/GlobalPreferences

This covers testing both Special:GlobalPreferences and Special:Preferences when you have globally set a user preference.

How it works

When you go to Special:GlobalPreferences, you can choose to make a user option global, and set its global value.
Afterwards, when you go to Special:Preferences on any wiki, you will see the user option you made global in step 1 greyed out and with an extra checkbox next to it.
If you click the new checkbox (in English called: "Set a local exception for this global preference") you can set the option to a different value for this wiki only.

Things to note

Different user options can behave differently. It is worth testing a broad variety of them on Special:GlobalPreferences and Special:Preferences.
Some options have dependencies on other options. For example, some options may only appear after enabling other options (e.g. phab:T294186#7538001, phab:T264150, phab:T292802)
Different wikis have different user options. It is worth testing across a variety of wikis (both language and project).
- N.B. the user options which appear in Special:GlobalPreferences depend on what options are available on the local wiki.
The UI might not correctly represent the actual user preferences in the database. See #Oracles.

Oracles

One thing to be aware of is that the UI might not correctly represent the actual user preferences in the database.

Two ways of dealing with this:

Disable javascript in the browser. This should eliminate any javascript related bugs. (How to do it in Firefox, Chrome)
Look in the database. These SQL queries will show the user preferences (locally and globally) for a single user:

SELECT user_properties.* FROM user_properties INNER JOIN actor ON actor_name="<username>" AND up_user=actor_user;
SELECT global_preferences.* FROM centralauth.global_preferences INNER JOIN centralauth.globaluser ON gu_name="<username>" AND gp_user=gu_id;

Scripts

You can use this javascript snippet on Special:GlobalPreferences to enable every option globally:

$( "input[name*='global']" ).click();

and then run this snippet on Special:Preferences to check every local override checkbox:

$( "input[name*='local-exception']" ).click();

and then this snippet to change the value of every user preference that is a checkbox:

$( "form#mw-prefs-form input:not([name*='local-exception'])" ).each( function( item ) { if ( this.type == "checkbox" ) { this.click() } } )