Using this gem, whenever a Capybara test in Cucumber, Rspec or Minitest fails, the HTML for the failed page and a screenshot (when using capybara-webkit, Selenium or poltergeist) is saved into $APPLICATION_ROOT/tmp/capybara.

Link via Binärgewitter Podcast (German).

For me guard recently took a very long to start (as in "minutes"), because I had lots of images in public/system.

Upgrading the listen gem (which is a dependency) to 2.7.7 fixed this.

As you know, assignable_values does not invalidate a record even when an attribute value becomes unassignable. See this example about songs:

class Song < ActiveRecord::Base
  belongs_to :artist
  belongs_to :record_label

  assignable_values_for :artist do
    record_label.artists
  end
end

We'll create two record labels with one artist each and create a song for one artist. When we change the song's record label, its artist is still valid.

makandra = RecordLabel.create! name: 'makandra records'
dominik...

assignable_values now supports Rails 4.1 and Ruby 2.1.0.

Travis CI is a free continuous integration testing service. However, it is really fragile and will break more than it will work.

If you choose to use it anyway, learn the lessons we already learnt:

Use a compatible Rubygems for Rails 2.3 on Ruby 1.8.7

Ruby 1.8.7 is not compatible with current Rubygems versions (> 2.0). Runnig rvm rubygems latest-1.8 --force will fix this and install Rubygems version 1.8.29.

To make Travis CI do this, add `before_script: rvm rubygems latest-1....

When you tell rbenv to install a Ruby it does not know about, you will get an error message.

$ rbenv install 2.1.2
ruby-build: definition not found: 2.1.2

You can list all available versions with `rbenv install --list'.

If the version you're looking for is not present, first try upgrading
ruby-build. If it's still missing, open a request on the ruby-build
issue tracker: https://github.com/sstephenson/ruby-build/issues

(Fun fact: Recent versions of ruby-build will give you a more helpful error message which...

EdgeRider 0.3.0 adds support for Rails 4.1 and Ruby 2.1. It forward-ports ActiveRecord::Base.scoped to Rails 4.1.

RSpec 3.0 deprecates the :should way of writing specs for expecting things to happen.

However, if you have tests you cannot change (e.g. because they are inside a gem, spanning multiple versions of Rails and RSpec), you can explicitly allow the deprecated syntax.

Fix

Inside spec/spec_helpber.rb, set rspec-expectations’ and/or rspec-mocks’ syntax as following:

RSpec.configure do |config|
  # ...
  config.mock_with :rspec do |c|
    c.syntax = [:should, :expect]
 ...

When you have a string containing umlauts which don't behave as expected (are not matched with a regexp, can't be found with an SQL query, do not print correctly on LaTeX documents, etc), you may be encountering umlauts which are not actually umlaut characters.

They look, depending on the font, like their "real" umlaut counterpart:

• ä ↔ ä
• ö ↔ ö
• ü ↔ ü

However, they are not the same:

'ä' == 'ä' # false
'ä'.size # 1
'ä'.size # 2

Looking at how those strings are constructed reveals what is going on:

'ä'.unpack('U*...

Warnings like those below may originate from rspec or shoulda-matchers or other gems that have not updated yet to the new MiniTest API.

One

Warning: you should require 'minitest/autorun' instead.
Warning: or add 'gem "minitest"' before 'require "minitest/autorun"'
# (backtrace)

Solution: Add gem 'minitest' to your Gemfile, before any rspec gem.

Another

MiniTest::Unit::TestCase is now Minitest::Test. From /Users/makandra/.rvm/rubies/ruby-1.9.3-p484/lib/ruby/1.9.1/tes...

So you want your Ruby script to install missing gems instead of dying? Take this method:

def installing_missing_gems(&block)
  yield
rescue LoadError => e
  gem_name = e.message.split('--').last.strip
  install_command = 'gem install ' + gem_name
  
  # install missing gem
  puts 'Probably missing gem: ' + gem_name
  print 'Auto-install it? [yN] '
  gets.strip =~ /y/i or exit(1)
  system(install_command) or exit(1)
  
  # retry
  Gem.clear_paths
  puts 'Trying again ...'
  require gem_name
  retry
end

Use it like this:

insta...

If you parse this Yaml ...

yes: 'Totally'
no: 'Nope'

... you get this Ruby hash:

{ true: 'Totally',
  false: 'Nope' }

In order to use the strings 'yes' and 'no' as keys, you need to wrap them with quotes:

'yes': 'Totally'
'no': 'Nope'

There's actually a long list of reserved words with this behavior:

y|Y|yes|Yes|YES|n|N|no|No|NO
|true|True|TRUE|false|False|FALSE
|on|On|ON|off|Off|OFF

I'm sorry.

You are probably using Ruby 1.8.7 with a too recent versions of Rubygems.

Downgrade your Rubygems to the latest version that works with 1.8.7.

See also

• Fix Rubygems warning: Gem.source_index is deprecated, use Specification
• Fix Rubygems binary error: undefined method `activate_bin_path' for Gem:Module (NoMethodError)
• [Bundler: Gemfile.lock is corrupt & gems are missing from the DEP...

There are 3 built-in file descriptors: stdin, stdout and stderr (std=standard). (You can define your own, see the linked article.)

Basic

• 0/1/2 references stdin/stdout/stderr
• >/2> redirects stdout/stderr, where > is taken as 1>
• &1/&2 references stdout/stderr
• &> redirects stdout and stderr = everything (caution: see below)

Caution: &> is functional as of Bash 4. This seems to result in a slightly differing behaviour when redirecting output in Ru...

Create, or edit your ~/.irbrc file to include:

require 'irb/ext/eval_history' # was 'irb/ext/save-history' for versions prior to Ruby 3.3
IRB.conf[:SAVE_HISTORY] = 2000
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-history"

quiet_assets helps with disabling asset pipeline log messages in the development log. When the gem is added, asset pipeline logs are suppressed by default.

If you want to disable muting temporarily, add config.quiet_assets = false to your config/application.rb.

Spring is a Rails application preloader. When debugging e.g. the rails gem, you'll be wondering why your raise, puts or debugger debugging statements have no effect. That's because Spring preloads and caches your application once and all consecutive calls to it will not see any changes in your debugged gem.

Howto

Disable spring with export DISABLE_SPRING=1 in your terminal. That will keep Spring at bay in that terminal session.

In Ruby, [you can only write environment variables that subproc...

General

Programatically invoke Rails generators

Require the generator, instantiate it and invoke it (because generators are Thor::Groups, you need to invoke them with invoke_all). Example:

 require 'generators/wheelie/haml/haml_generator'
 Generators::HamlGenerator.new('argument').invoke_all

Other ways: Rails invokes its generators with Rails::Generators.invoke ARGV.shift, ARGV. From inside a Rails generator, you may call the [inherited Thor method invoke(args=[], options={}, config={})](https://github...

docopt helps you define interface for your command-line app, and automatically generate parser for it.

docopt is based on conventions that are used for decades in help messages and man pages for program interface description. Interface description in docopt is such a help message, but formalized. Here is an example:

Naval Fate.

Usage:
  naval_fate ship new <name>...
  naval_fate ship <name> move <x> <y> [--speed=<kn>]
  naval_fate ship shoot <x> <y>
  naval_fate mine (set|remove) <x> <y> [--moored|--drifting]
  naval_fate -h |...

Rubygems can produce lots of deprecation warnings, but sometimes, you cannot fix them. To have a tidy terminal with output that matters, add this to the top of your Gemfile and enjoy silence:

Deprecate.skip = true if defined?(Deprecate.skip)
Gem::Deprecate.skip = true if defined?(Gem::Deprecate.skip)

# all gems go here ...

(Inspiration)

If you want to label things with a color but don't actually care which cholor, you can use the attached Colorizer class.

To get a completely random color (some of which will clash with your design):

Colorizer.colorize(some_object) # => "#bb4faa"

To get similiar colors (e. g. bright, pale colors of different hues):

 # random hue, saturation of 0.5, lightness of 0.6
Colorizer.colorize_similarly(some_object, 0.5, 0.6) # => "#bbaaaa"

Also see the color gem.

better_errors is an awesome gem for enhanced error pages in development, featuring a live-REPL for some light debugging.

To debug the exception you got on an AJAX-Request, visit /__better_errors on your app's root path (e.g. http://localhost:3000/__better_errors). It shows the error page for the last exception that occurred, even when it has been triggered by an AJAX request.

If you want to do JavaScript-style camelization, ActiveSupport's String#camelize method can actually help you out. Simply pass a :lower argument to it.

>> 'foo_bar_baz'.camelize
=> "FooBarBaz"
>> 'foo_bar_baz'.camelize(:lower)
=> "fooBarBaz"