Spreewald gives you the <step> within <selector> meta step that will constrain page inspection to a given scope.

Unfortunately, this does not work with RSS feeds, as they're XML documents and not valid when viewed from Capybara's internal browser (e.g. a <link> tag cannot have content in HTML).

Inspecting XML

If you're inspecting XML that is invalid in HTML, you need to inspect the page source instead of the DOM. You may use Spreewald's "... in the HTML" meta step, or add this proxy step fo...

When you find yourself in the situation that you would like to define a custom matcher in your specs, but you do not want to define a global matcher since you need it only for your specific test, there are two ways to do it:

Custom matcher for a single group

If you're only going to include a matcher once, you can also use the matcher macro within an example group:

describe "group" do
  
  matcher :be_just_like do |expected|
    match {|ac...

To delay your entire Jasmine test suite until the DOM is ready, add the following:

beforeAll(function(done) {
  $(done);
});

fake_stripe spins up a local server that acts like Stripe’s and also serves a fake version of Stripe.js, Stripe’s JavaScript library that allows you to collect your customers’ payment information without ever having it touch your servers. It spins up when you run your feature specs, so that you can test your purchase flow without hitting Stripe’s servers or making any external HTTP requests.

We've also had tests actually hitting the testing sandbox of Stripe, which worked OK most of the time (can be flakey).

When you run rake db:rollback and nothing happens, you are probably missing the latest migration file (or have not migrated yet).

$ rake db:rollback
$ 

If that happens to you, check your migration status.

$ rake db:migrate:status
   up     20160503143434  Create users
   up     20160506134137  Create pages
   up     20160517112656  Migrate pages to page versions
   up     20160518112023  ********** NO FILE **********

When you tell Rails to roll back, it tries to roll back the latest change that was mi...

ActiveRecord offers an explain method similar to using EXPLAIN SQL statements on the database.

However, this approach will explain all queries for the given scope which may include joins or includes.

Output will resemble your database's EXPLAIN style. For example, it looks like this on MySQL:

User.where(id: 1).includes(:articles).explain

EXPLAIN for: SELECT `users`.* FROM `users`  WHERE `users`.`id` = 1
+----+-------------+-------+-------+---------------+
| id | select_type | table | type  | possible_keys |
+----+-----...

When dealing with time zones in Rails, there is one key fact to keep in mind:

Rails has configurable time zones, while
Ruby is always in the server's time zone

Thus, using Ruby's time API will give you wrong results for different time zones.

"Without" time zones

You can not actually disable time zones, because their existence is a fact. You can, however, tell Rails the only single time zone you'll need is the server's.

config.time_zone = "Berlin" # Local time zone
config.active_record.default_timezone = :loca...

Expecting a primitive value as an argument to a method invocation is easy:

expect(object).to receive(:foo).with('arg1', 'arg2')

This expectation would be met with this call:

object.foo('arg1', 'arg2')

But what if the argument is expected to be an object with a given set of methods? E.g. this class with #first_name and #last_name methods:

class Person

  def initialize(first_name, last_name)
    @first_name = first_name
    @last_name = last_name
  end
  
  attr_reader :first_name, :last_name
  
end
``...

Cucumber's docstrings let you add long strings to a step like this:

# foo.feature
Given this text:
"""
First line
Second line

Second Paragraph
"""

# foo_steps.rb
Given /^this text:$/ |docstring|
  puts docstring.split
end

You see these neat triple double quotes ("""). Now what to do when you need your docstring to contain triple double quotes, too?

# Does not work:
Given this text:
"""
Docstrings work like this:
  """
  Docstring example
  """
You see?
"""

Update: Official solution

You can escape the inner quotes ...

OAuth requires a set of params to be carried along requests, among which a nonce. Some libraries pass these along as headers, some as query parameters. All fine.

When you're using VCR, the latter case is an issue. By default, requests are matched on method and URI. However, no request URI will equal another when they include a nonce. You won't be able to match these requests with VCR.

Solution

Obviously you need to...

You can use JavaScript to get or set cookie values on the client.

Using the vanilla JavaScript API

In JavaScript, document.cookie is an accessor to all cookies on the current site. It looks like a String, but its setter is actually more powerful.

When setting cookies this way, remember to set the path=/ option.

Reading cookies

A result may look like this:

hello=universe; foo=bar

This means that there are 2 cookies: "hello" with value "universe", and "foo" with value "bar...

jQuery's deferred objects behave somewhat like standard promises, but not really.

One of many subtle differences is that there are two ways to chain callbacks to an async functions.

The first one is done, which only exists in jQuery:

$.ajax('/foo').done(function(html) {
  console.debug("The server responded with %s", html);
});

There is also then, which all promise libraries have:

$.ajax('/foo').then(function(html) {
  console.debug("The server resp...

The NestedHash class allows you to read and write hashes of any depth. Examples:

hash = {}
NestedHash.write hash, 'a', 'b', 'c', 'value' # => { a: { b: { c: 'value' } } }
NestedHash.read hash, 'a', 'b', 'c' # => 'value'
NestedHash.read hash, 'a' # => { b: { c: 'value' } }
NestedHash.read hash, 'foo', 'bar' # => undefined

Inspired by victusfate.

Code

class @NestedHash

  @read: (objekt, keys...) ->
    if objekt and keys.length
      @read objekt[keys[0]], keys[1...]...
    ...

RSpec provides a nice diff when certain matchers fail.

Here is an example where this diff is helpful while comparing two hashes:

{a:1}.should match(a:1, b:2)

Failure/Error: {a:1}.should match(a:1, b:2)
  expected {:a=>1} to match {:a=>1, :b=>2}
  Diff:
  @@ -1,3 +1,2 @@
   :a => 1,
  -:b => 2,

Unfortunately, this diff is not as clever as it would need to. RSpec's instance_of matchers will look like errors in the diff (even if they are not), and time objects that differ only in milliseconds won't appear in the ...

tl;dr

• Don't write resources :people, :concerns => :trashable

• Write

  resources :people do
    concerns :trashable
  end
  

Why

Writing a controller spec I encountered this error:

Failure/Error: get :index
ActionController::RoutingError:
  No route matches {:controller=>"people"}

caused by this route definition

resources :people, :concerns => :trashable

which renders strange routes:

      trash_person PUT    /people/:id/trash(.:format)             people#check {:concerns=>:trashable}
          ...

If you want to configure your nginx to drop connections to a specific location, you can do so by responding with HTTP response code 444.

Status 444 is a non-standard response code that nginx will interpret as "drop connection".

Example:

server {
  listen 127.0.0.1;
  
  location /api/ {
    return 444;
  }
}

An example use case is reverse-proxying with nginx and simulating a route that drops connections.

TL;DR There are three dimensions you can control when scoping routes: path helpers, URL segments, and controller/view module.

scope module: 'module', path: 'url_prefix', as: 'path_helper_name' do
  resources :examples, only: :index
end

as → prefixes path helpers: path_helper_name_examples_path and path_helper_name_examples_url
path → prefixes URL segments: /url_prefix/examples
module → nests the controller: controller Module::ExamplesController, found at app/controllers/module/examples_controller.rb with views ...

Our preferred way of testing ActiveRecord is to simply create/update/destroy the record and then check if the expected behavior has happened.

We used to bend over backwards to avoid touching the database for this. For this we used a lot of stubbing and tricks like it_should_run_callbacks.

Today we would rather make a few database queries than have a fragile test full of stubs.

Example

Let's say your User model creates a first Project on cr...

RSpec supports a one-liner syntax for setting an expectation on the subject:

describe Array do
  describe "when first created" do
    it { should be_empty }
  end
end

The example description "it should be empty" will be defined automatically.

With RSpec 3's expect-based syntax you use it_is_expected instead:

describe Array do
  describe "when first created" do
    it { is_expected.to be_empty }
  end
end

Validations should be covered by a model's spec.

This card shows how to test an individual validation. This is preferrable to save an entire record and see whether it is invalid.

Recipe for testing any validation

In general any validation test for an attribute :attribute_being_tested looks like this:

1. Make a model instance (named record below)
2. Run validations by saying record.validate
3. Check if record.errors[:attribute_being_tested] contains the expected validation error
4. Put the attribute into a valid state
5. Run...

If you expect method calls in RSpec 3, be aware that the argument matchers use very liberal equality rules (more like === instead of ==).

For example:

expect(subject).to receive(:foo).with(MyClass)

subject.foo(MyClass)      # satisfies the expectation
subject.foo(MyClass.new)  # also satisfies the expectation

expect(subject).to receive(:bar).with(/regex/)

subject.bar(/regex/)      # satisfies the expectation
subject.bar('regex')      # also satisfies the expectation

This is usually not an issue, except when your method ...

In JavaScript we often use Immediately Invoked Function Expessions (or IIFEs) to prevent local variables from bleeding into an outside scope:

(function() {
  var foo = "value"; // foo is scoped to this IIFE
})();

In Coffeescript an IIFE looks like this:

(->
  foo = "value" # foo is scoped to this IIFE
)()

There is also a shorthand syntax with do:

do ->
  foo = "value" # foo is scoped to this IIFE

You can also use do with arguments t...