Object cache active notice

[r-a-y]

When a user is logged in, we always fetch the active notice.

Let's object cache this unnecessary query as notices rarely change.

[r-a-y]

Attached patch:

• Introduces a new hook - 'messages_notice_before_delete' to do something before a notice is deleted
• Adds object caching to the get_active() method
• Adds an invalidation function to bp-messages-cache.php
• Adds a unit test

I guess what I need feedback on is the unit test. Should I be putting all the asserts in my one method? Or should I split them up into a different file? I kind of lumped them altogether since the asserts are related to one another.

[boonebgorges]

Unit test looks fine to me. Theoretically you could split it into two tests, but it's fine to put them together. (Only practical difference is that when you do multiple assertions in a single test, and one fails, the rest of the assertions in that test are not run. So if you're going to put them together, make sure they're closely linked and would likely be broken by the same bug.)

I'm pretty sure do_action_ref_array() is not necessary here. do_action( 'messages_notice_before_delete', $this ) will pass the object by reference automatically, as of PHP 5.0.

[r-a-y]

In 7994:

Add object caching when fetching the active notice.

This commit:

• Introduces a new hook - 'messages_notice_before_delete' to do something before a notice is deleted
• Adds object caching to the BP_Messages_Notice::get_active() method
• Adds a cache invalidation function to bp-messages-cache.php
• Adds a unit test

Fixes #5419