How to install the `xelatex` binary on Ubuntu 14.04
Just install the texlive-xetex package:
sudo apt-get install texlive-xetex
Running integration tests without texlive-xetex will produce an error during xelatex execution:
RTeX::Document::ExecutableNotFoundError
A nicer way to run RSpec and/or Cucumber
geordi, our collection of awesome shell scripts, has been extended by three scripts to help you call RSpec or Cucumber:
cuc
This script runs Cucumber the way you want it:
- Prints some line feeds to easily find your test results when you come back to the console later
- Configures Cucumber to use cucumber_spinner if it is available in your
Gemfile - Runs Cucumber under
bundle exec - Uses an old version of Firefox for Selenium (Javascript) features...
Error "execution expired (Timeout::Error)" when using Selenium and Webmock
If you get the above error when running tests in bulk (but not individually), it's actually the fault of Webmock.
Updating Webmock to version 1.7+ fixes this.
Fix a spec that only runs when called directly
When a spec only runs when it is called directly, but not as part of the whole test suite, make sure the filename is foo_spec.rb instead of just foo.rb.
Waiting for page loads and AJAX requests to finish with Capybara
If you're using the Capybara webdriver, steps sometimes fail because the browser hasn't finished loading the next page yet, or it still has a pending AJAX request. You'll often see workarounds like
When I wait for the page to load
Then ...
Workarounds like this do not work reliably, will result in flickering tests and should be avoided. There is no known reliable way to detect if the browser has finished loading the page.
Solution
Instead you should wait until you can observe the result of a page load. E.g. if y...
Testing Cookie Limits
TL;DR If you want to support most browsers, then don't exceed 50 cookies per domain, and don't exceed 4093 bytes per domain (i.e. total size of all cookies <= 4093 bytes)
Behind the link, you'll find a simple HTML page that offers some cookie tests (how large, how many etc) and an overview of this data for various browsers.
Fun fact: You cannot delete cookies with a key that hits the size limit and has a small value.
CoffeeScript
Imagine all the syntactical delights of Ruby and Haml for your JavaScript. You write in a nice language, but get normal JavaScript at runtime. All whilst having full access to 3rd-party JavaScript libraries (jQuery, PrototypeJS), debugging support (it becomes pure, readable JavaScript), existing support from test suites (it’s normal JavaScript) and growing support from various text editors (TextMate, Vim, Emacs).
Structuring Rails applications: the Modular Monorepo Monolith
Root Insurance runs their application as a monolithic Rails application – but they've modularized it inside its repository. Here is their approach in summary:
Strategy
- Keep all code in a single repository (monorepo)
- Have a Rails Engine for each logical component instead of writing a single big Rails Application
- Build database-independent components as gems
- Thus: gems/ and engines/ directories instead of app/
- Define a dependency graph of components. It should have few edges.
- Gems and Engines can be extracted easier once nece...
Error "undefined method last_comment"
This error message may occur when rspec gets loaded by rake, e.g. when you migrate the test database.
NoMethodError: undefined method 'last_comment' for #<Rake::Application:0x0055a617d37ad0>
Rake 11 removes a method that rspec-core < 3.4.4 depends on. To fix, lock Rake to < 11 in your Gemfile:
gem 'rake', '< 11', # Removes a method that rspec-core < 3.4 depends on
Web Operations 101 For Developers
This post is not about devops, it's not about lean startups, it's not about web scale, it's not about the cloud, and it's not about continuous deployment. This post is about you, the developer who's main purpose in life has always been to build great web applications. In a pretty traditional world you write code, you write tests for it, you deploy, and you go home. Until now.
How to hide your selenium browser window with "headless"
Note: While the solution in this card should still work, we prefer another solution now: Hide your Selenium browser window with a VNC server.
If you would like to hide the annoying selenium browser window that always gets the focus and prevents you from working, you can use the headless gem. This note provides some instructions how you can get it to work with your cucumber accepta...
RSpec < 2.11: ActiveRecord scopes must be loaded before using the "=~" matcher
To test whether two arrays have the same elements regardless of order, you can use the =~ matcher in RSpec < 2.11:
actual_array.should =~ expected_array
If either side is an ActiveRecord scope rather than an array, you should call to_a on it first, since =~ does not play nice with scopes:
actual_scope.to_a.should =~ expected_scope.to_a
If you use RSpec >= 2.11 we recommend using the match_array or contain_exactly matchers instead of =~.
Use the eq matcher only if the order of records matters.
Know what makes your browser pant
I figure we needed a definitive reference for what work is triggered by changing various CSS properties. It's something I get asked about often enough by developers, and while we can do tests with DevTools, I have both the time and inclination to shortcut that for everyone. I'm nice like that. —Paul Lewis
How much should I refactor?
The Rails community has been abuzz with object-oriented programming, SOLID principles, laws, design patterns, and other principles, practices, and patterns. We’ve (re)discovered new tools and techniques to separate and reuse logic, making code easier to test, understand, and maintain. Now that we’ve learned about all these new tools, when do we use them?
New geordi script: migrate-all
Use the command geordi migrate to migrate your databases and to prepare them before running tests. The abbrevation geordi m works as well.
- It will run
rake db:migrateif parallel_tests does not exist in your Gemfile - Otherwise it runs
b rake db:migrateand then executesb rake parallel:prepareif parallel_tests was found in your Gemfile.
Error during Rails 5 upgrade: Environment data not found in the schema
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.
RSpec: Expect one of multiple matchers to match
RSpec let's you chain a matcher with .or. The expectation will then pass if at least one matcher matches:
expect(color).to eq("red").or eq("green")
Real-world example
A real-world use case would be to test if the current page has a button with the label "Foo". There are many ways to render a button with CSS:
<input type="button" value="Foo">
<input type="submit" value="Foo">
<button>Foo</button>
We cannot express it with a single have_css() matcher, since we need the { text: 'Foo' } optio...
yujinakayama/transpec: The RSpec syntax converter
A comprehensive script to convert test suites from RSpec 2 to RSpec 3. This converts more than should/expect syntax.
httpbin: HTTP Client Testing Service
Some dozen generic API endpoints you can use to test how your HTTP client deals with various responses, e.g.
- a slow connection
- many redirects
- compressed data
I found this useful while debugging an issue with timeouts.
Wrapping Your API In A Custom Ruby Gem
Nice tutorial about packaging Ruby bindings to your API in a Ruby gem, with tests using VCR casettes.
mattheworiordan/capybara-screenshot
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).
BrowserStack has browser plugins for local testing
Local testing allows you to test your private and internal servers using the BrowserStack cloud, which has support for firewalls, proxies and Active Directory.
Stubbing out external services with an embedded Sinatra application
One of many useful techniques when your test suite needs to talk to a remote API.
mattheworiordan/capybara-screenshot
Takes a screenshot when you call it, or when a test fails.