This error is raised because your old database does not have a configured environment yet, which Rails 5 enforces.

If this error occurs while migrating your parallel test databases, make sure to update the parallel_tests gem first: current versions fix this. If you're still using Cucumber < v3, the latest version of parallel_tests will be 2.18.0.

Rails applications and ruby gems should have a README that gives the reader a quick overview of the project. Its size will vary as projects differ in complexity, but there should always be some introductory prose for a developer to read when starting on it.

Purpose

That's already the main purpose of a project README: Give a new developer a quick overview of the project. In sketching this outline, the README should notify the reader of any peculiarity he needs to know of.

Remember that in a few months, you'll be a kind of "new ...

When making requests using curl, no cookies are sent or stored by default.
However, you can tell curl to re-use cookies received earlier (or forge your own cookies).

There are 2 command line switches you need to use:

• -c will write cookies to a given file
• -b will read cookies from a given file

Example

The remote server sets a "foo" cookie to value "bar". We tell curl to store them to a file at /tmp/cookies using the -c switch.

$ curl -c /tmp/cookies http://httpbin.org/cookies/set?foo=bar

You may look at the file, ...

You should avoid using application models in your migrations. But how else could you create records in a migration?

The most basic way is to write plain SQL, but since INSERT statements are no pleasant write for Rubyists, here is a simple wrapper:

Record creation helper for migrations

The helper method below takes a table name and a hash of attributes, which it inserts into the specified table. Copy it over to your migration and profit!

  private

  def insert_record(table, **attributes)
    attributes.merge!...

The gist is:

• wrap the text with a span
• use line-height for the spacing between lines ("margin")
• use box-shadow to control the line background size ("padding")

Example

span
  box-shadow: 0 0 0 10px #fff
  background-color: #fff
  box-decoration-break: clone # Fix Firefox
  line-height: 2.2

→ [jsfiddle](https://jsfiddle.net/2fmqgbh...

Situation: You want to write a spec for a function inside an Angular service. This function at some point makes an API request and acts upon response. Notably, your Angular app employs uiRouter, although it is not used nor actually required for this test.

Working test setup

# Capitalized expressions are intended to be replaced with YOUR values

describe 'SERVICE', ->

  beforeEach ->
    module 'MODULE'

    module ($urlRouterProvider) ->
      # Prevent uiRouter's initialization, i.e. do not sync the current URL
      # with its r...

If you try to listen to events on elements that are nested inside a <fieldset disabled>, Firefox will stop event propagation once the event reaches the fieldset. Chrome and IE/Edge will propagate events.

Since we often bind event listeners to document this can be annoying.

You could solve it by...

• ...adding event listeners on elements themselves. Note that this is terrible when you have many elements that you'd register events for.
• ...adding event listeners on a container inside the <fieldset>, around your eleme...

By default, browsers will not wrap text at syllable boundaries. Text is wrapped at word boundaries only.

This card explains some options to make browsers wrap inside a long word like "Donaudampfschifffahrt".

Option 1: hyphens CSS property (preferred)

Modern browsers can hyphenate natively. Use the hyphens CSS property:

hyphens: auto

There is also hyphens: none (disable hyphenations even at ­ entities) and hyphens: manual (hy...

HTTPie consists of a single http command designed for painless debugging and interaction with HTTP servers, RESTful APIs, and web services

It easy to use and has very nice defaults and coloured output which makes it good for local testing.

Usage examples with curl equivalent:

# curl post
curl --data "foo=23&bar=42" https://example.org/blub
# httpie post
http https://example.org/blub foo=23 bar=42

# curl localhost
curl localhost:3000/users
# httpie localhost
http :3000/users

PostgreSQL's Common Table Expressions (CTEs) can be used to extract sub-queries from bulky SQL statements into a temporary table to be referenced instead.

This is most useful to avoid ugly joins or sub-selects. CTEs can be used for SELECT, INSERT, UPDATE or DELETE.

Example (from the PostgreSQL docs):

WITH regional_sales AS (
        SELECT region, SUM(amount) AS total_sales
        FROM orders
        GROUP BY region
     ), top_regions AS (
        SELECT region
        FROM regional_sales
        WHERE total_sales > (SE...

PostgreSQL supports the SQL OVERLAPS operator. You can use it to test if two date ranges overlap:

=> SELECT ('2001-02-16'::date, '2001-12-21'::date) OVERLAPS
          ('2001-12-20'::date, '2002-10-30'::date);

overlaps
--------
true

An important caveat is that the date ranges are defined as start <= time < end. As such the later date is not included in the range:

=> SELECT ('2001-02-16'::date, '2001-12-21'::date) OVERLAPS
          ('2001-12-21'::date, '2002-10-30'::date);

overlaps
--------
false

Also compar...

Summary: Don't add chromedriver-helper to the Gemfile

• the executables might break your tests in projects where chromedriver-helper is not in the Gemfile
• developers with different chrome versions will have problems using the same chromedriver-helper version

Background

If you install the chromedriver-helper gem, but don't have it in you Gemfile, your selenium tests might fail with:

Selenium::WebDriver::Error::WebDriverError: unable to connect to chromedriver 127.0.0.1:9515

The reason is that chromedriver-helper ov...

In most projects I know, Cucumber test suite speed is not an issue. Of course, running 350 features takes its time, but still each test for itself is reasonably fast. There is nothing you can do to fundamentally speed up such a test (of course, you should be using parallel_tests).

However, in projects that go beyond clicking around in a web GUI and checking results, there might be various measures to speed things up. Katapult tests for example could be sped up more than 4 times by re...

Sometimes when working with VCR you still want to use webmock. Since VCR hooks into webmock and fails when an unknown request is happening, you have to turn it off in order to use webmock like you are used to. Here is how to do this in rspec.

RSpec.configure do |config|
  config.around do | example |
    if example.metadata[:turn_off_vcr]
      VCR.turn_off!
      example.run
      VCR.turn_on!
    else
      example.run
    end
  end
end

When you're using Sidekiq::Web to monitor the Sidekiq status AND have your session cookie configured to a wildcard domain like .example.com, you need to take an additional step to keep your cookies valid.

Issue

Sidekiq::Web is mounted into your Rails application and will use the Rails session cookie for protection from CSRF attacs. While it somehow figures out the cookie name, it does NOT respect cookie configuration like a custo...

Requestb.in is a webservice that gives you a temporary URL you can use to test request. The page will automatically record and display the latest web request made to it.

We're usually running Ubuntu LTS versions. Sometimes newer hardware requires packages from more recent Ubuntu releases that only come with 6 months of support. If there is really no other way, it's possible to install packages from later Ubuntu releases

Caution: Pay really close attention to what you're doing. Depending on the package, this process may require upgrading a lot of dependencies, possibly breaking the system! You really should not do this unless you've carefully calculated the impact on your system

Preparation

First,...

Checking if a JavaScript value is of a given type can be very confusing:

• There are two operators typeof and instanceof which work very differently.
• JavaScript has some primitive types, like string literals, that are not objects (as opposed to Ruby, where every value is an object).
• Some values are sometimes a primitive value (e.g. "foo") and sometimes an object (new String("foo")) and each form requires different checks
• There are three different types for null (null, undefined and NaN) and each has different rules for...

RSpec allows you to mark a single Example/ExampleGroup so that only this will be run. This is very useful when using a test runner like guard.

Add the following config to spec/spec_helper.rb:

RSpec.configure do |config|
  # These two settings work together to allow you to limit a spec run
  # to individual examples or groups you care about by tagging them with
  # `:focus` metadata. When nothing is tagged with `:focus`, all examples
  # get run.
  config.filter_run_including :focus => true
  config.run_all_when_everything_filtere...

If you already selected an element and want to get its parent, you can call find(:xpath, '..') on it.

To get the grand-parent element, call find(:xpath, '../..').

Example

Find a link which contains a twitter icon and check that it links to the correct page:

<a href="http://twitter.com/">
  <i class="icon is-twitter"></i>
</a>

link = page.find("a .icon.is-twitter").find(:xpath, '..')
expect(link[:href]).to eq("http://twitter.com/")

About XPath

There is a good overview on XPath syntax on [w3schools](htt...

When an Rspec example fails, I usually investigate by running that example again using rspec <file:line>. However, this does not work with shared examples, since Rspec doesn't know in which context the shared example should be run.

But there is a different way: You can run the shared example using the -e, --example option. It takes a string value and runs all scenarios containing that substring in their full description.

This allows you to run a single uniquely named example, all examples with
similar names, all the examples in a u...

Precondition

• You are not using javascript tests
• The file is served from a public folder (not via controller)

Problem description

If you deliver files from a public folder it might be that the Content-Disposition header is not set. That's why the following spreewald step might raise an error:

Then I should get a download with filename "..."

expected: /filename="some.pdf"$/
     got: nil (using =~) (RSpec::Expectations::ExpectationNotMetError)

Solution

One solution...

An end-to-end test (E2E test) is a script that remote-controls a web browser with tools like Selenium WebDriver. This card shows basic techniques for fixing a flaky E2E test suite that sometimes passes and sometimes fails.

Although many examples in this card use Ruby, Cucumber and Selenium, the techniques are applicable to all languages and testing tools.

Why tests are flaky

Your tests probably look like this:

When I click on A
And I click on B
And I click on C
Then I should see effects of C

A test like this works fine...

Slides for Henning's talk on Sep 21st 2017.

Understanding sync vs. async control flow

Talking to synchronous (or "blocking") API

print('script start')
html = get('/foo')
print(html)
print('script end')

Script outputs 'script start', (long delay), '<html>...</html>', 'script end'.

Talking to asynchronous (or "evented") API

print('script start')
get('foo', done: function(html) {
  print(html)
})
print('script end')

Script outputs 'script start', 'script end', (long ...