Cucumber: Clear localStorage after each scenario
Capybara clears cookies before each scenario, but not other client-side data stores. If your app is using localStorage
or sessionStorage
, contents will bleed into the next scenario.
Use this hook to remove all site data after each scenario:
After do
if Capybara.current_driver == :selenium && !Capybara.current_url.starts_with?('data:')
page.execute_script <<-JAVASCRIPT
localStorage.clear();
sessionStorage.clear();
JAVASCRIPT
end
end
Rails: wrap_parameters for your API
Rails 5 (don't know about the others) comes with an initializer wrap_parameters.rb
. Here you can tell rails to wrap parameters send to your controllers for specific formats into a root node which it guesses from the controller name.
ActiveSupport.on_load(:action_controller) do
wrap_parameters format: [:json]
end
This would wrap a flat json body, like
{"name": "Konata"}
that gets send to your UsersController
into
{"name" => "Konata", "user" => {"name" => "Konata"}}
Note that the params are now duplicat...
Selenium cannot obtain stable Firefox connection
When using geordi for integration tests you might get the following error when trying to run geordi cucumber
:
unable to obtain stable firefox connection in 60 seconds (127.0.0.1:7055) (Selenium::WebDriver::Error::WebDriverError)
This means, that the vnc window the tests is talking to has no proper firefox version running. To figure out the issue this might help you:
- Check if the
.firefox-version
(e.g.24.0
) is the same as~/bin/firefoxes/24.0/firefox
says in the browser - Maybe [rest...
How to make Webpacker compile once for parallel tests, and only if necessary
Webpack is the future. We're using it in our latest Rails applications.
For tests, we want to compile assets like for production.
For parallel tests, we want to avoid 8 workers compiling the same files at the same time.
When assets did not change, we do not want to spend time compiling them.
Here is our solution for all that.
Its concept should work for all test suites.
Copy the following to config/initializers/webpacker_compile_once.rb
. It will patch Webpacker, but only for the test
environment:
# Avoid hardcoded asset host...
Cucumber: Test that an element is not overshadowed by another element
I needed to make sure that an element is visible and not overshadowed by an element that has a higher z-index
(like a modal overlay).
Here is the step I wanted:
Then the very important notice should not be overshadowed by another element
This is the step definition:
Then(/^(.*?) should not be overshadowed by another element$/) do |locator|
selector = selector_for(locator)
expect(page).to have_css(selector)
js = <<-JS
var selector = #{selector.to_json};
var elementFromSelector = document.querySelector(selector)...
Clicking issues with chromedriver
ChromeDriver clicking works by simulating a mouse click in the middle of the element's first client rect (or bounding client rect if it doesn't have a first client rect). (Clicking issues)
So if you are trying to click on an element, chromedriver
tries to click at the position where it first finds that element.
This can lead to some problems and unexpected behavior like:
-
Element is not clickable at point ...
erros - Another element which is now located at...
Git: rebase dependent feature branch after squash
This card will show you how to use git rebase --onto
without confusion.
Use case:
You've got two feature branches (one
and two
), where two
depends on one
. Now commits of branch one
have changed after you branched two
from it (i.e. after code review the commits of branch one
are squashed). Thus the commit history of branch one
has changed. Branch two
's history however didn't change.
Solution:
To make the branches share the same commit history again you will have to rebase and replay (attach) the a...
Middleman configuration for Rails Developers
Middleman is a static page generator that brings many of the goodies that Rails developers are used to.
Out of the box, Middleman brings Haml, Sass, helpers etc. However, it can be configured to do even better. This card is a list of improvement hints for a Rails developer.
Gemfile
Remove tzinfo-data
and wdm
unless you're on Windows. Add these gems:
gem 'middleman-livereload'
gem 'middleman-sprockets' # Asset pipeline!
gem 'bootstrap-sass' # If you want to use Bootstrap
gem 'byebug'
gem 'capistrano'
gem 'capistrano-mid...
Style Guide for Git commit messages
- Separate subject from body with a blank line
- Limit the subject line to 50 characters (max. 72), include reference (unique story ID) to requirements tracker (Linear in our case)
- Capitalize the subject line
- Do not end the subject line with a period
- Use the imperative mood in the subject line
- Wrap the body at 72 characters
- Use the body to explain what and why vs. how.
Tip
As an alternative, use a commit message that refers to a GitHub issue (
fixes #321
) or [story ID](https://makandracards.com/makandra/620718-b...
RubyMine users: you should be using bookmarks
RubyMine allows bookmarking lines of code. This is super-helpful when working on a complex problem.
I've been using this feature for a few years now, and so should you! :)
Here are the default Linux/Windows keystrokes. See the documentation for other keybindings.
Add an anonymous bookmark
F11
A gray checkmark will be shown in the gutter on the left.
If you press F11
again on a bookmarked line, the bookmark will be removed.
Add a named bookmark ("mnemonic")
Ctrl
...
How to disable Chrome's save password bubble for Selenium tests
When filling out forms in Selenium tests, Chrome shows the (usual) bubble, asking to store those credentials.
While the bubble does not interfere with tests, it is annoying when debugging tests. Here are two ways to disable it:
Option 1: prefs
You can set profile preferences to disable the password manager like so:
prefs = {
'credentials_enable_service' => false,
'profile.password_manager_enabled' => false
}
Capybara::Selenium::Driver.new(app, browser: :chrome, prefs: prefs)
Sadly, there are no command line s...
ruby-sass: Do not use comments between selector definitions
Sass lets you easily specify multiple selectors at once like this:
.some-block
&.has-hover,
&:hover
outline: 1px solid red
This will add a red outline on either real hover or when the has-hover
class is present. However, adding a comment will void the definition of that line:
.some-block
&.has-hover, // From hoverable.js <-- DON'T
&:hover
outline: 1px solid red
... will simply drop the &.has-hover
part in ruby-sass(deprecated). [sassc](https://rubygems.org/g...
Beware: Nested Spreewald patiently blocks are not patient
Note: The behaviour of Spreewald's within
step is as described below for version < 1.9.0; For Spreewald >= 1.9.0 it is as described in Solution 1.
When doing integration testing with cucumber and selenium you will often encounter problems with timing - For example if your test runs faster than your application, html elements may not yet be visible when the test looks for them. That's why Spreewald (a collection of cucumber steps) has a concept of doing things patiently
, which means a given b...
ActiveRuby
Looks like ActiveState is trying to market a new Ruby distribution for Enterprises:
ActiveRuby Enterprise Edition is designed for businesses with large Ruby deployments in essential, mission-critical applications that, when down, could cost your business in lost revenue and a damaged reputation. Deploy Ruby with confidence knowing you're using the most secure, enterprise-grade builds for the platforms that power your business. You'll get priority access to our Ruby experts for technical support and best prac...
The pitfalls of postMessage
The postMessage API is an alternative to JSONP, XHR with CORS headers and other methods enabling sending data between origins. It was introduced with HTML5 and like many other cross-document features it can be a source of client-side vulnerabilities.
CSS tests and experiments
The pages listed here contain tests and experiments about features, possibilities, browsers’ bugs concerning CSS.
That is, over 200 experiments.
CSS font metrics in detail
Line-height and vertical-align are simple CSS properties. So simple that most of us are convinced to fully understand how they work and how to use them. But it’s not. They really are complex, maybe the hardest ones, as they have a major role in the creation of one of the less-known feature of CSS: inline formatting context.
For example, line-height can be set as a length or a unitless value 1, but the default is normal. OK, but what normal is? We often read that it is (or should be) 1, or maybe 1.2, even the CSS spec is unclear on that...
Bug in Chrome 56+ prevents filling in fields with slashes using selenium-webdriver/Capybara
There seems to be a nasty bug in Chrome 56 when testing with Selenium and Capybara: Slashes are not written to input fields with fill_in
. A workaround is to use javascript / jquery to change the contents of an input field.
Use the following code or add the attached file to your features/support/
-directory to overwrite fill_in
.
module ChromedriverWorkarounds
def fill_in(locator, options = {})
text = options[:with].to_s
if Capybara.current_driver == :selenium && text.include?('/')
# There is a nasty Bug in Chrome ...
Capybara: Disable sound during Selenium tests
If the application under test makes sound, you probably want to disable this during integration testing.
You can use the args
option to pass parameters to the browser. For Chrome:
Capybara.register_driver :selenium do |app|
Capybara::Selenium::Driver.new(app, browser: :chrome, args: ["--mute-audio"])
end
I haven't found a corresponding command line option for Firefox.
Hat tip to kratob.
How to search through logs on staging or production environments
We generally use multiple application servers (at least two) and you have to search on all of them if you don't know which one handled the request you are looking for.
Rails application logs usually live in /var/www/<project-environment-name>/shared/log
.
Web server logs usually live in /var/www/<project-environment-name>/log
.
Searching through single logs with grep
/ zgrep
You can use grep
in this directory to only search the latest logs or zgrep
to also search older (already zipped) logs. zgrep
is used just like grep
...
How to tackle complex refactorings in big projects
Sometimes huge refactorings or refactoring of core concepts of your application are necessary for being able to meet new requirements or to keep your application maintainable on the long run. Here are some thoughts about how to approach such challenges.
Break it down
Try to break your refactoring down in different parts. Try to make tests green for each part of your refactoring as soon as possible and only move to the next big part if your tests are fixed. It's not a good idea to work for weeks or months and wait for all puzzle pieces ...
It's OK to put block elements inside an <a> tag
In general, you should not put a block element inside an inline element. So don't do this:
<span>
<div>text</div>
</span>
The browser will think you wrote invalid HTML by accident, and will sometimes reorder elements silently.
There is one notable exception: It's OK to wrap block elements in a <a>
tag in HTML5 (not 4). The spec says:
The a element may be wrapped around entire paragraphs, lists, tables, and so forth, even entire sections, so long ...
Howto use ActiveRecord preload with plain SQL inner joins
Like you know from "How to tell ActiveRecord how to preload associations (either JOINs or separate queries)", you can tell ActiveRecord explicitly if it should use a LEFT OUTER JOIN
or a separate query to preload associations.
Here is some special case, where a simple includes
is not possible. For the diagram below we want to sort the rides
by the translated name of the departure_place
and the arrival_place
:
 and open VNC for Firefox.
Features:
- It does not freeze your server like when you're using a debugger. (Compared to the
Then console
step) - It enables interacting with the server. (Compared to taking screenshots in Capybara)
- It is a faster alternat...