So you're getting an error message like the following, although your Gemfile lists shoulda-matchers and it has always worked:

NoMethodError:
  undefined method `allow_value' for #<RSpec::ExampleGroups::Person::Age:0x007feb239fa6a8>

This is due to Rails 4.1 (specifically, Spring) revealing a weak point of shoulda-matchers -- jonleighton explains why.

Solution

The solution is to follow [the gem's installation guide](https://github.com/thoughtbot/sh...

Aruba is an extension to Cucumber that helps integration-testing command line tools.

When your tests involve a Rails test application, your tool's Bundler environment will shadow that of the test application. To fix this, just call unset_bundler_env_vars in a Cucumber Before block.

Previously suggested solution

Put the snippet below into your tool's features/support/env.rb -- now any command run through Aruba (e.g. via #run_simple) will have a clean Bundler envir...

An all-in-approach to fix the problem of pending AJAX requests dying in the browser when the server ends a test or switches scenarios.

We were able to work around this issue in most projects by doing this instead:

After '@javascript' do
  step 'I wait for the page to load'
end

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).

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...

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....

A little-known feature of modern Regexp engines that help when optimizing a pattern that will be matched against long strings:

An atomic group is a group that, when the regex engine exits from it, automatically throws away all backtracking positions remembered by any tokens inside the group.

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]
 ...

Sometimes you're getting an ActiveSupport deprecation warning that you cannot or don't want to fix. In these cases, it might be okay to silence some specific warnings. Add this to your initializers, or require it in your tests:

silenced = [
  /Not considered a useful test/,
  /use: should(_not)? have_sent_email/,
] # list of warnings you want to silence

silenced_expr = Regexp.new(silenced.join('|'))

ActiveSupport::Deprecation.behavior = lambda do |msg, stack|
  unless msg =~ silenced_expr
    ActiveSupport::Deprecation::DEFAULT_BEHAVI...

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...

SimpleForm is a great approach to simplifying your forms, and it comes with lots of well-defined input types. However, the :grouped_select type seems to be overly complicated for most use cases.

Example

Consider this example, from the documentation:

form.input :country_id, collection: @continents,
  as: :grouped_select, group_method: :countries

While that looks easy enough at a first glance, look closer. The example passes @continents for a country_id.\
SimpleForm actua...

If you get this error when you try to resize an OpenStack instance:

# nova resize example 23 --poll
ERROR: Resize requires a change in size. (HTTP 400)

You need to change your flavor to have a different memory size. It's a bug in an older OpenStack version:

        # /nova/compute/api.py
        if (current_memory_mb == new_memory_mb) and flavor_id:		
            raise exception.CannotResizeToSameSize()

which got fixed 2012-09-12 ([https://git.openstack.org/cgit/openstack/nova/commit/nova/compute/api.p...

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...

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 |...

So you have a restangular collection and you want to remove an element from it, after you've successfully deleted it from the server.

The README suggests to say something like $scope.users = _.without($scope.users, user). While that works at first glance (the element is no longer in your collection), it will break horribly when you want to use restangular's attributes on that collection.

This...

Sometimes you may want to print files from the command line, especially when you have lots of them.
You can use lp for that.

To print a single example.pdf file on your default printer, simply say:

lp example.pdf

lp accepts multiple filenames, so to print all PDF files in the current directory:

lp *.pdf

You can specify a printer via the -d switch:

lp -d YOUR_PRINTER_NAME *.pdf

Your printer's name is then one you defined on your system. You can check with your CUPS configuration by visiting `http://localhost:631/...

Use the following command to test if a server (in this example: makandra.com on port 443) uses Perfect Forward Secrecy (PFS):

openssl s_client -connect makandra.com:443 -cipher ECDHE-RSA-RC4-SHA

You should see something like the following:

~ > openssl s_client -connect projecthero.com:443 -cipher ECDHE-RSA-RC4-SHA
CONNECTED(00000003)
depth=1 O = AlphaSSL, CN = AlphaSSL CA - G2
verify error:num=20:unable to get local issuer certificate
verify return:0
---
Certificate chain
 0 s:/C=DE/OU=Domain Control Va...

Enter the hostname of a server to test it for CVE-2014-0160.

When using TextMate2 with the cucumber bundle, it does not recognize step definitions (e.g. custom_steps.rb) as such but believes they are plain Ruby files. But there is help!

Solution

Add these lines to the bottom of your .tm_properties file (in ~/ for global settings, in any directory for per-project settings):

[ "*_steps.rb" ]
fileType = "source.ruby.rspec.cucumber.steps"

Apparently, this works for any files. Define a regex and specify custom settings. The attached article lists all available configuration options (whic...