Run Selenium tests in Chrome instead of Firefox
Here is how to switch your Selenium to Chrome:
- Make sure you've got a recent version of chromedriver in your
$PATH
See also geordi chromedriver_update which is automatically executed before every usage of geordi cucumber
.
- Register Driver:
Create a file features/support/capybara.rb
with the following content for recent version of Capybara:
Capybara.register_driver :selenium do |app|
Capyb...
How to access Chrome Devtools when running JavaScript tests via CLI
While we are used to run our JavaScript tests on a test page within our Browser, it's also possible to run them on the command line with NodeJS. I think that's actually the most common way to run JS tests.
Given a Vue project that uses Jest (via vue-cli-service
) with the following package.json
:
{
"scripts": {
"test": "vue-cli-service test:unit --testMatch='**/tests/**/*.test.js' --watch"
},
}
This allows us to run J...
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...
Rails: How to test the parsed response body
Testing your responses in Rails allows to parse the body depending on the response MIME type with parsed_body
.
get '/posts.json'
response.parsed_body # => [{'id' => 42, 'title' => 'Title'}, ...]
For JSON APIs we often parse the response as symbolized keys with JSON.parse(response.body, symbolize_names: true)
, which is not supported by parsed_body
. For all other cases you might want to drop JSON.parse(response.body)
and replace it w...
RSpec: How to test the content of a flash message in a request spec
The ActionDispatch module of Rails gives you the helper method flash
to access the flash messages in a response.
describe PostsController, type: :request do
describe 'update' do
it 'shows a success message on update' do
post_record = create(:post)
put "/posts/#{post_record.id}"
# Same as @request.flash[:alert]
expect(flash[:alert]).to eq('Post updated successfully.')
end
end
end
Capybara: Preventing headless Chrome from freezing your test suite
We prefer to run our end-to-end tests with headless Chrome. While it's a very stable solution overall, we sometimes see the headless Chrome process freeze (or the Capybara driver losing connection, we're not sure).
The effect is that your test suite suddenly stops progressing without an error. You will eventually see an error after a long timeout but until then it will seem that your suite is frozen. If you're also using [capybara-screenshot](https:/...
How to employ and run your tests with parallel_tests to speed up test execution
When your cucumber features grow massively over time, the test execution can take a lot of time.
One easy way to speed up your test execution is to use the parallel_tests gem.
It comes along with some useful rake tasks that let you setup your local test environment shortly to run your features, specs or unit-tests in parallel.
Follow these steps to get it to work.
-
Add the parallel_tests gem to your
Gemfile
test sections like that:# ./Gemfile group :development, :test do
...
Migrate gem tests from Travis CI to Github Actions with gemika
We currently test most of our gems on Travis CI, but want to migrate those tests to Github Actions. This is a step-by-step guide on how to do this.
Note that this guide requires the gem to use gemika.
- Go to a new "ci" branch:
git checkout -b ci
- Update gemika to version >= 0.5.0 in all your Gemfiles.
- Have gemika generate a Github Actions workflow definition by running
mkdir -p .github/workflows; bundle exec rake gemika:generate_github_actions_workflow > .github/workf...
Chromedriver: Disabling the w3c option might break your integration tests with Chrome 91
We recently noticed issues with Chrome 75+ when having the w3c
option enabled within the Selenium webdriver. It looks like recent Selenium versions don't have any issues with the w3c interface anymore. And starting with Chrome 91 this fix might cause unexpected issues, so you should try to enabled this option again or just remove the following line from you configuration:
options.add_option('w3c', false)
Background: Setting the w3c
option t...
Jasmine: Spy on value properties
Jasmine has spyOnProperty()
, but it only works if the property is implemented using getter and setter functions. This is a known limitation of Jasmine.
If the mocked property is a simple value, it will not work:
const x = { foo: 1 }
console.log(x.foo) // 1
spyOnProperty(x, 'foo').and.returnValue(2)
// Throws: Error: <spyOnProperty> : Property foo does not have access type get
Below you can find a function `spyOnValuePr...
Run a single test in Test::Unit
To run a single test file:
rake test:units TEST=test/unit/post_test.rb
rake test:functionals TEST=test/functional/posts_controller_test.rb
rake test:integration TEST=test/integration/admin_news_posts_test.rb
You may even run a single test method:
ruby -I test test/unit/post_test.rb -n "name of the test"
ruby -I test test/functional/posts_controller_test.rb -n test_name_of_the_test # underscored, prefixed with 'test_'
Or all tests matching a regular expression:
ruby -I test test/integration/admin_news_posts_test.r...
How to test print stylesheets with Cucumber and Capybara
A print stylesheet is easy to create. Choose a font suited for paper, hide some elements, done. Unfortunately print stylesheets often break as the application is developed further, because they are quickly forgotten and nobody bothers to check if their change breaks the print stylesheet.
This card describes how to write a simple Cucumber feature that tests some aspects of a print stylesheets. This way, the requirement of having a print stylesheet is manifested in your tests and cannot be inadvertedly removed from the code. Note that you can...
ActionMailer: How to send a test mail directly from the console
If your rails application is unable to send mails, it might be useful to debug your settings using the rails console. Here is a snippet that shows the current settings and lets you send a test mail directly from the console:
mailer = ActionMailer::Base.new
# check settings:
mailer.delivery_method # -> :smtp
mailer.smtp_settings # -> { address: "localhost", port: 25, domain: "localhost.localdomain", user_name: nil, password: nil, authentication: nil, enable_starttls_auto: true }
# send mail:
mailer.mail(from: 'sender@example.com', ...
Rails: Concurrent requests in development and tests
With puma
you can have concurrent requests. There are two concepts on how Puma can handle two incoming requests: Workers and Threads.
Workers
Puma can have multiple workers. Each worker is a process fork from puma and therefore a very heavy instance and can have multiple threads, that handle the incoming requests.
Example: A Puma server with 2 workers
and 1 thread
each can handle 2 request in parallel
. A third request has to wait until the thread of one of the workers is free.
Threads
Rails is thread-safe since version 4 (n...
How to clear cookies in Capybara tests (both Selenium and Rack::Test)
Capybara drivers will usually delete all cookies after each scenario. If you need to lose cookie data in the middle of a scenario, you can do this:
browser = Capybara.current_session.driver.browser
if browser.respond_to?(:clear_cookies)
# Rack::MockSession
browser.clear_cookies
elsif browser.respond_to?(:manage) and browser.manage.respond_to?(:delete_all_cookies)
# Selenium::WebDriver
browser.manage.delete_all_cookies
else
raise "Don't know how to clear cookies. Weird driver?"
end
Hunt down that elusive debug message in Ruby
When you just went through a long debug-fest and infested your code with dozens of debug messages, it can be hard to find all those calls to puts
and p
. This note describes a hack that lets you trace those messages in your code.
Let's say you want to get rid of a console message "foobar". Copy the Undebug
class below to config/initializers.rb
. In the same initializer, type a line:
Undebug.trace_message('foobar')
Now run tests or whatever you need to do to to trigger that message. The console output should look like this:
...
Firefox: Focus-sensitive Selenium tests do not work reliably in parallel test execution
This is a problem when using Selenium with Firefox. We recommend using ChromeDriver for your Selenium tests.
Firefox will not trigger focus/blur events when its window is not focused. While this makes sense in standard usage, it breaks in parallel test execution.
Please do not rely on focus events in your tests. The linked card has an example of how to build passing tests that deal with focus/blur events.
How to generate and test a htpasswd password hash
Generate a password
htpasswd -Bn firstname.lastname
This will ask you for a password and use bcrypt (-B
, more secure) and print the output to stdout (-n
).
Check if password matches the hash
You'll first have to write the password hash to a file:
echo firstname.lastname:$2y$05$4JXxd2GM/J2...9c3KJmFS > htpass_test
Check, if it is correct:
htpasswd -v htpass_test firstname.lastname
You probably should not use the -b
switch to read the password from the command line as the password will then be visible...
Preparing your test database: mind the differences
Instead of running all missing migrations on your test database with rake db:migrate RAILS_ENV=test
you can also use a handful of rake tasks to prepare the database structure directly. They can produce different results, though.
In a nutshell, to ensure your test database gains the correct structure:
- Don't use
rake db:test:prepare
carelessly - or use
rake db:test:clone_structure
← preferred :) - or use
rake db:migrate RAILS_ENV=test
and don't mix it with other ways, like some of the rake tasks.
rake db:test:prepare
------------...
How to: Run geordi in a single proccess with parallel test setup
Geordi uses parallel_tests if available for running the test suite. To debug an application it is very unhandy to have multiple processes as your terminal I/O will not work as expected once a breakpoint is hit.
Even parallel_tests
support an option to enable a single process run, it is not possible to pass this option through geordi. But you can set the number of processes via ENV variable
manually:
PARALLEL_TEST_PROCESSORS=1 bundle exec geordi cucu...
Test that an exception or error page is raised in Capybara
You can use these step definitions:
Then /^I should not see an error$/ do
(200 .. 399).should include(page.status_code)
end
Then /^I should see an error$/ do
(400 .. 599).should include(page.status_code)
end
Note that you need to tag the scenario with @allow-rescue
to test that an error is shown like this
@allow-rescue
Scenario: Accessing the admin area requires a login
When I go to the admin area
Then I should see an error
These step definitions will not work for @javascript
scena...
Debugging flickering VCR tests
We often use VCR to stub external APIs. Unfortunately VCR can have problems matching requests to recorded cassettes, and these issues are often hard to debug.
VCR's error messages mostly look like this and are not very helpful:
An HTTP request has been made that VCR does not know how to handle:
POST http://another-site.de:9605/json/index
VCR fails if the request does not exactly look like the request it has recorded. If the request is d...
How to provoke Selenium focus issues in parallel test processes
As attachments to this card you will find a Cucumber feature and supplementing step definition that you can use to provoke Selenium focus issues that only occur when two focus-sensitive Selenium scenarios run at the same time (probably with parallel_tests). This can help you to detect and fix flickering integration tests.
The attached feature works by going to your root_path
and focusing a random form element every 5...
Test redirects to an external URL with Cucumber/Capybara
When a controller action redirects to an external URL (like http://somehost.com/some/path
) you will find that this is hard to test with Cucumber and Capybara:
- A non-Javascript Rack::Test scenario will just ignore the host and try to open
/some/path
in your local application - A Selenium test will actually follow the redirect, which you probably don't want either
There are two workarounds for this. You can use either, or a combination of both.
- Write a controller spec
Controller specs can test if a resp...