Improve the testing guide [ci skip]

Improve the "Testing Rails Applications" guide adding a section for
testing helpers and a little note about associations with ActiveRecord
and YAML fixtures.

Also add a link to Fixture Builder ; yet another replacement for
fixtures such as Machinist or FactoryGirl.
Remove conditional, since results are always an instance of `ActiveRecord::Result`
Added SanitizeHelper to rails guide docs [ci skip]

Added SanitizeHelper to rails guide docs [ci skip]

Added SanitizeHelper to rails guide docs update [ci skip]
Creating an SSE class to be used with ActionController::Live.
Added Action View in 'rake about' [ci skip]
Remove privatizing of Fixnum#/ from assert_distance_of_time_in_words

MRI reimplemented Date in C so it doesn't hit this division anymore
while JRuby still uses the old stdlib implementation of Date so
it will always hit this.

With this change the actionview date_helper_test.rb tests should pass on JRuby.
Merge pull request #11771 from atambo/jruby_assert_distance_of_time_in_words

Remove privatizing of Fixnum#/ from assert_distance_of_time_in_words
added String#to_date documentation to Rails 4 upgrade guide

[ci skip]
#11759: Update Assets Pipeline Guide

by default included to precompile only non-js/css files from `app/assets` and `application.(css|js)`
adding a weird test case
Merge pull request #11778 from jetthoughts/11759_update_assets_guides

Update Assets Pipeline Guide [ci skip]
Add CHANGELOG entry for #11767

[ci skip]
asakusa.rb hack night!

Fix in-memory tests
Fix indentation
Use the proper encoding comment on the file
Add a missing require.

This makes the rack_logger_test.rb runnable by itself (outside of the `rake test` suite).
"Naked" rescue clauses only catch StandardError subclasses.

Similar to #11497.
Merge pull request #11780 from thedarkone/logger-naked-rescue-fix

Rack::Logger naked rescue fix
test to express that we can't turn non-array columns to array columns.

Closes #11062
Removing obsolete html tags in favor of markdown code block.