There are three ways to define your own RSpec matchers, with increasing complexibility and options:

1) Use RSpec::Matchers.define

RSpec::Matchers.define :be_a_multiple_of do |expected|
  match do |actual|
    actual % expected == 0
  end
  
  # optional
  failure_message do |actual|
    "expected that #{actual} would be a multiple of #{expected}"
  end
  
  # optional
  failure_message_when_negated do |actual|
    "expected that #{actual} would not be a multiple of #{expected}"
  end
end

• This is automatically available i...

When you need to add a event listener to hundreds of elements, this might slow down the browser.

An alternative is to register an event listener at the root of the DOM tree (document). Then wait for events to bubble up and check whether the triggering element (event.target) matches the selector before you run your callback.

This technique is called event delegation.

Performance considerations

Because you only register a single listener, registering is ...

A well-written API can be a great asset to the organization that wrote it and to all that use it. Given the importance of good API design, surprisingly little has been written on the subject. In this talk (recorded at Javapolis), Java library designer Joshua Bloch teaches how to design good APIs, with many examples of what good and bad APIs look like.

When you roll custom URLs with hacks like routing-filter, you can put a spec like this into spec/routing/routing_spec.rb:

Spreewald has steps that let you test that e-mails have been sent, using arbitrary conditions in any combination.

The attached file is for legacy purposes only.

Don't use should validate_format_of(...) because that matcher works in weird ways. Use the allow_value matcher instead:

describe Email, '#sender' do
  # > Rspec 3 should syntax
  it { should allow_value("email@addresse.foo").for(:sender) }
  it { should_not allow_value("foo").for(:sender) }
  
  # Rspec 3 expect syntax
  it { is_expected.to allow_value("email@addresse.foo").for(:sender) }
  it { is_expected.not_to allow_value("foo").for(:sender) }
end

Errors that may occur if you do use should validate_format_of(...):
...

You can write regular expressions some different ways, e.g. /regex/ and %r{regex}. For examples, look here.

Remember that it is always a good idea to match a regex visually first.

Characters

Literal Characters

[ ] \ ^ $ . | ? * + ( )

Character Classes

[ae]            matches a and e, e.g. gr[ae]y => grey or gray => but NOT graay or graey
[0-9]  ...

The following example is from the Cucumber wiki:

Given a blog post named "Random" with Markdown body
  """
  Some Title, Eh?
  ==============
  Here is the first paragraph of my blog post. Lorem ipsum dolor sit amet,
  consectetur adipiscing elit.
  """

That multi-line string will be given as the last block argument in your step definitions:

Given /^a blog post named "([^\"]*)" with Markdown body$/ do |title, markdown|
  Post.create!(:title =...

Our awesome collection of rspec helpers (formerly known as "spec_candy.rb") is now available as a gem. It works, it is tested and there will be updates.

Usage

Add rspec_candy to your Gemfile.

Add require 'rspec_candy/helpers' to your spec_helper.rb, after the rspec requires.

List of features

See on GitHub

An alternative to this technique is using VCR. VCR allows you to record and replay real HTTP responses, saving you the effort to stub out request/response cycles in close details. If your tests do require close inspection of requests and responses, Webmock is still the way.

WebMock is an alternative to FakeWeb when testing code that uses the network. You sh...

This will tunnel HTTP requests to one given domain and port through an intermediary SSH server:

ssh -L 8080:targethost:80 tunnelhost

http://localhost:8080 will now connect you to http://targethost:80, tunnelling all data through tunnelhost via SSH.

Note that the connection between tunnelhost and targethost will still be unencrypted in this example.

For example, to send a form and populate a preview div with the response.

$('content_form').request({
  parameters: { 'preview': "1" }, // overrides parameters
  onComplete: function(transport){ 
    $('previewContent').update(transport.responseText); 
  }
});

A fake filesystem. Use it in your tests.

When a Cucumber feature leaves your page through an external Link, Webrat has problems like "Could not find field: "E-mail" (Webrat::NotFoundError)" using your page afterwards. It will also have trouble following redirects.

Fix it with this step:

Given /^I am back on my page$/ do
  webrat_session.header("Host", "www.example.com")
end

This may be awkward to set up, but will work once you're done.

Fun facts:

• In case of a connection loss the slave will try to reconnect to the master server and resume replication for the next 24 hours
• If you want to use your slave as a "real" MySQL server, you basically need to switch off replication (STOP SLAVE; RESET SLAVE; and reset your my.cnf) and restart the MySQL daemon.

Master server configuration

• Create replication user

  In the MySQL shell:

  CREATE USER 'replicator'@'%' IDENTI...
  

Most of these will not work in newer projects because these use the Capybara/Rack::Test combo in lieu of Webrat.

Find input fields

Then /^there should be a "([^"]+)" field$/ do |name|
  lambda { webrat.current_scope.send(:locate_field, name) }.should_not raise_error(Webrat::NotFoundError)
end

Then /^there should be no "([^"]+)" field$/ do |name|
  lambda { webrat.current_scope.send(:locate_field, name) }.should raise_error(Webrat::NotFoundError)
end

Find html content

Then /^I should see "([^\"]*)...

With defaults, RCov doesn't work the way you how you would like it to. To create a nice test coverage report, copy the attached file to lib/tasks/rcov.rake. After that rake rcov:all will run all RSpec examples and Cucumber features. The report will be written RAILS_ROOT/coverage/index.html.

Here is what the task does in detail:

• Generates aggregated coverage of both RSpec and Cucumber
• Works with Rails 2 and Rails 3
• Reports for app/**/*.rb and nothing else
• If called with an environment variable IGNORE_SHARED_TRAITS=true it ...

We built cucumber_spinner to have a progress bar for Cucumber features, which also outputs failing scenarios as soon as they fail.

Installation

gem install cucumber_spinner

Usage

cucumber --format CucumberSpinner::ProgressBarFormatter

If you use CucumberSpinner::CuriousProgressBarFormatter and a feature fails, the according page will show up in your browser.

Note that if you run your Cucumber tests using the [cuc](https://makandracards.com/makandra/1277-a-nicer-way-to-...

To test concurrent code, you will need to run multiple threads. Unfortunately, when you use blocking system calls (e.g. locks on the database), Ruby 1.8 threads won't work because system calls will block the whole interpreter.

Luckily you can use processes instead. fork spins off a new process, IO.pipe sends messages between processes, Process.exit! kills the current process. You will need to take care of ActiveRecord database connections.

Here is a full-fledged example:

describe Lock, '.acquire' do

  before :each do
  ...

rspec_spinner is a progress bar for RSpec which outputs failing examples as they happen (instead of all at the end).

Installation

gem install rspec_spinner

Usage

script/spec -r rspec_spinner -f RspecSpinner::Bar -c

To make a shortcut in your .bashrc

alias ss='script/spec -r rspec_spinner -f RspecSpinner::Bar -c'

There's also an alternate runner RSpecSpinner::Spinner which shows a spinner and the name of the current spec instead of a progress bar.

Install gem and plugin

sudo gem install parallel
script/plugin install git://github.com/grosser/parallel_tests.git

Adapt config/database.yml

test:
  database: xxx_test<%= ENV['TEST_ENV_NUMBER'] %>

Create test databases

script/dbconsole -p
CREATE DATABASE `xxx_test2`;
...

Generate RSpec files

script/generate rspec

(you'll probably only let it overwrite files in script/)

Prepare test databases...

To parse XML-documents, I recommend the gem nokogiri.

A few hints:

• xml = Nokogiri::XML("<list><item>foo</item><item>bar</item></list>") parses an xml string. You can also call Nokogiri::HTML to be more liberal about accepting invalid XML.
• xml / 'list item' returns all matching nodes; list item is used like a CSS selector
• xml / './/list/item' also returns all matching nodes, but .//list/item is now an XPath selector
  • XPath seems to be triggered by a leading ....

• sudo gem install gettext --no-ri --no-rdoc
• sudo gem install fast_gettext --no-ri --no-rdoc
• script/plugin install git://github.com/grosser/gettext_i18n_rails.git (didn't work as gem)
• environment.rb: see code example at the bottom
• if this is your first translation: cp locale/app.pot locale/de/app.po for every locale you want to use
• use method "_" like _('text') in your rails code
• run rake gettext:find to let GetText find all translations used
• translate messages in 'locale/de/app.po' (leave msgstr blank and ms...

When you need to patch an existing gem, one way is to "vendor" the gem by copying it into the vendor/gems directory of your Rails project. You can then make any changes you require and Rails will use the vendored version of the gem after a server restart. Unfortunately you need to perform some additional steps to marry Rails and the copied gem. This notes describes what to do.

With Bundler

This is super-painful. If you just copy the gem to vendor/gems, Rails will complain:

Unpacked gem foolib in vendor/gems has no s...