Category: Ruby

Silencing noise in the Rails development log
The standard Rails development log contains a lot of noise that is rarely meaningful for debugging. The Quiet Assets gem is a mandatory part of my Rails development process as it removes the logging noise of the asset pipeline.

Also, if WEBrick is used as a development server, the following entry is logged for each asset pipeline log entry (whether silenced or not by Quiet Assets):
```
WARN Could not determine content-length of response body.
Set content-length of the response or set Response#chunked = true
```
While some have suggested monkey-patching WEBrick or installing Thin as an alternate server (which doesn’t work under JRuby), the simplest way to remove those statements is to add WEBrick specifically in your Gemfile:
```
gem 'webrick', '~&gt; 1.3.1', group: :development
```
20 Dec 2012
Mixing DatabaseCleaner transaction and truncation strategies
RSpec by default issues a database transactional rollback that is executed after the completion of a block. When using Capybara with the :js option (to enable testing with Selenium or Webkit), the transactional rollback offered by RSpec is unusable as the browser is loaded via a separate thread and has a separate database connection. Thus any uncommitted data cannot be read by the browser.

Most people suggest employing DatabaseCleaner using a truncation strategy to overcome this deficiency. The performance of cleaning via truncation vs transaction depends on the size of data – with smaller fixtures, transactions are preferable.
Instead of using one or the other, we can mix strategies to have the best of both worlds:
```
config.use_transactional_fixtures = false # Using DatabaseCleaner instead

config.before(:suite) do
DatabaseCleaner.strategy = :transaction # Default strategy
DatabaseCleaner.clean_with(:truncation) # Initially clean with truncation
end

config.before(:each, type: :request) do
# Swap to truncation as Selenium runs in separate thread with a different
# database connection
DatabaseCleaner.strategy = :truncation
end

config.after(:each, type: :request) do
# Reset so non-request specs can use transaction
DatabaseCleaner.strategy = :transaction
end

config.before(:each) do
DatabaseCleaner.start
end

config.after(:each) do
DatabaseCleaner.clean
end
```
On my current test suite of around 461 tests with 73 request specs, this dropped the run time by just over a minute.
19 Dec 2012
Mocking instances created via ActiveRecord’s find
Most Ruby mocking frameworks have the ability to mock a new object created via a constructor. However, when an object is created via ActiveRecord’s find or find_by_* methods, the .new method isn’t invoked. Instead, the .instantiate method is called.

For example, to specify :instantiate as the object creation method using FlexMock:
```
flexmock(Dog).new_instances(:instantiate)
.should_receive(:bark)
.at_least.once
.and_return(:woof)
```
3 Dec 2012
Persisting IRB & Rails Console History
Continuing the theme on customising IRB and Rails Console, add these lines to ~/.irbrc to persist the command history across console sessions:
```
require 'irb/ext/save-history'
IRB.conf[:SAVE_HISTORY] = 100
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb_history"
```
27 Nov 2012
Awesome Print your IRB & Rails Console
Awesome Print is a Ruby gem that prints prettified objects to the console. To avoid having to prepend ap to all your console commands, set it as the default formatter in IRB and Rails by adding the following to your ~/.irbrc:
```
require 'awesome_print'
IRB::Irb.class_eval do
def output_value
ap @context.last_value
end
end
```
Obviously, Awesome Print first needs to be installed: gem install awesome_print

UPDATE: Awesome Print now includes a method to make the integration process easier.
```
require 'awesome_print'
AwesomePrint.irb!
```
23 Nov 2012