Some key highlights and points from the linked article TestProf II: Factory therapy for your Ruby tests.

The Problem with Factories in Ruby Tests

• Factories are used to easily generate test data.
• However, they can unintentionally slow down test suites by creating unnecessary or excessive associated data (factory cascades).

Understanding Factory-Induced Slowdowns

• Factories often create additional data (e.g., associated records) th...

Rails default config uses the ActiveSupport::Cache::NullStore and disables controller caching for all environments except production:

config.action_controller.perform_caching = false
config.cache_store = :null_store

If you want to test caching you have at least two possibilities:

1. Enable caching for every test (not covered by this card and straightforward)
2. Enable caching for individual test

Enable caching for individual test (file cache)

1. Leave the defau...

Attaching files to a field that is handled by Carrierwave uploaders (or maybe any other attachment solution for Rails) in tests allows different approaches. Here is a short summary of the most common methods.

You might also be interested in this card if you see the following error in your test environment:

CarrierWave::FormNotMultipart:
You tried to assign a String or a Pathname to an uploader, for security reasons, this is not allowed.
If this is a file upload, please check that your upload form is multipart encoded.

Factor...

In modern default RSpec configurations, your tests are usually run in random order. This helps to detect "flickering" tests that only fail when run in a certain order.

The reason for this are tests that have side effects causing other tests to fail later. The hard part is to find the offending test.

Enter rspec --bisect:

1. Say you have a flickering test that passes on its own, but you just saw it fail in a full test run. At the top of the RSpec output, you will see a message like Randomized with seed 12345. Take a note of the number....

For Selenium tests, your browser starts in your local timezone, or whatever your system's environment specifies.
This is usually good enough. To test any timezone-dependent behavior in Chrome, you can change the time zone using the Chrome DevTools Protocol.

Example

Chrome accepts any IANA time zone name, like "Europe/Berlin" or "Asia/Tokyo".
Here is the relevant command for Capybara:

page.driver.browser.execute_cdp('Emulation.setTimezoneOverride', timezoneId: 'Asia/Tokyo')
``...

When you don't only have a favicon.ico in your project but also PNGs of different sizes and backgrounds, you should test if all those files are actually reachable.

Here are a few selectors to get you started:

    'link[rel~="icon"]' # regular ones, matches "shortcut icon" and "icon"
    'link[rel="apple-touch-icon"]' # iOS
    'meta[content][name="msapplication-TileImage"]' # IE11
    'meta[content][name^="msapplication-square"]' # IE11

A s...

You have an async function that rejects:

async function failingFunction() {
  throw new Error("Something went wrong")
}

When you call that function in a test, your test will fail:

it('has a test', function() {
  failingFunction() // this will fail your test
})

The failure message will look like this:

Unhandled promise rejection: Error: Something went wrong

You can fix this by expecting the state of the returned promise:

it('has a test', async function() {
  await expectAsync(failingFunction()).toBeRej...

The linked article suggests an interesting way to speed up tests of Rails + Postgres apps:

PostgreSQL allows the creation of “unlogged” tables, which do not record data in the PostgreSQL Write-Ahead Log. This can make the tables faster, but significantly increases the risk of data loss if the database crashes. As a result, this should not be used in production environments. If you would like all created tables to be unlogged in the test environment you can add the following to your...

Sometimes you want to write a test for a business rule that's based on multiple variables. In your goal to cover the rule thoroughly, you start writing tests for each permutation of all variables. Quickly it blows up into something unsustainable. With n variables for the business rule, you get 2n permutations/test cases. This is manageable with 2 variables (4 test cases), but at 3 variables (8 test cases) it becomes ridiculous, and anything beyond that feels immediately uncomfortable.

I've noticed myself using an alternate pattern for...

The problem

Unpoly's [up-observe], [up-autosubmit] and [up-validate] as well as their programmatic variants up.observe() and up.autosubmit() are a nightmare for integration tests.

Tests are usually much faster than the configured up.form.config.observeDelay. Therefore, it may happen that you already entered something into the next field before unpoly updates that field with a server response, discarding your changes.

The steps I wait for active ajax requests to complete (if configured) and capybara-lockstep can catch some ...

Imagine you want to write a cucumber test for a user-to-user chat. To do this, you need the test to work with several browser sessions, logged in as separate users, at the same time.

Luckily, Capybara makes this relatively easy:

Scenario:

Scenario: Alice and Bob can chat
  Given Alice, Bob, and a chat session
  When I am signed in as "Alice"
    And I go to the chat
    And I am signed in as "Bob" [session: bob]
    And I go to the chat [session: bob]
    And I send the message "Hello, this is Alice!"
  Then I should see "Hello, this ...

If you use transactional_fixtures or the database_cleaner gem with strategy :transaction, after_commit callbacks will not be fired in your tests.

Rails 5+

Rails 5 has a fix for this issue and no further action is needed.

Rails 3, Rails 4

Add the gem test_after_commit to your test group in the Gemfile and you are done. You don't need to change the database strategy to deletion (wh...

Fresh Chrome installations now show a "Choose your search engine" popup in Europe. This might make your Cucumber tests fail.

Fortunately there is a flag to disable the popup. Add the following option to your chromedriver setup code:

options.add_argument('--disable-search-engine-choice-screen')

I found this flag in Peter Beverloo's list.

Background: This was experienced locally with google-chrome 127.0.6533.72. In CI I did not get the popup.

There is a way to use multiple databases in Rails.
You may have asked yourself how you're able to keep your test databases clean, if you're running multiple databases with full read and write access at the same time. This is especially useful when migrating old/existing databases into a new(er) one.

Your database.yml may look like this:

default: &default
  adapter: postgresql
  encoding: unicode
  username: <%= ENV['DATABASE_USER'] %>
  host: <%= ENV['DATABASE...

To navigate between test and test subject Rubymine requires you to set the test root sources as Test Sources Root.

In case you are using the keyboard shortcut "CTRL + ALT + SHIFT + c" to copy the reference path + you have set the "Test Sources Root" for your test folders, you might consider setting this keyboard to "Copy From Repository Root". This will return the path `spec/foo_spec....

I recently was in a weird situation where my (Jest/CLI) tests were referencing a function that was no longer part of my code - I had just refactored it.

Apparently Jest has some kind of cache that caused the issue, running npx jest --clearCache solved it for me.

Within development and test environments, Rails is usually configured to show a detailed debug page instead of 404s. However, there might be some cases where you expect a 404 and want to test for it.

An example would be request-specs that check authorization rules. (If you use a gem like consul for managing authorization rules, you should always check these rules via power-specs. However, request-specs can be used as a light-weight version of integration tests here.)

In this case, Rails will replace the 404 page that you want to test ...

When you need to see the content of a page (i.e. not all the HTML but the relevant text body)

• you can do pp (html_content)
  • pp will format the html String human readable pretty printed
• where html_content can be replaced by one of the following commands:

Rails

body or response.body

Capybara:

• page.driver.html.content
• page.body

Webrat:

Nokogiri::HTML(response.body).content

The returned strings can be cleaned up by calling .gsub(/^\s*$/, '').squeeze("\n") on them.\
Although this may be useful for d...

PostCSS is a tool for transforming styles with JS plugins. In Webpacker you can configure the plugins and their settings via the postcss.config.js file. Make sure that postcss-loader is part of your package.json.

module.exports = {
  plugins: [
    require('postcss-import'),
    require('postcss-flexbugs-fixes'),
    require('postcss-preset-env')({
      autoprefixer: {
        flexbox: 'no-2009'
      },
      stage: 3
    })
  ]
}

Note: Stage 3 means you can use all CSS features that ar...

With this command you can run all the spec files which have been edited or added in the current branch since master:

git diff --name-only master -- ./spec | xargs -I{} rspec {} 

• If you have several spec folders add them for path parameter after ./spec accordingly.
• The option -I{} creates a placeholder to be replaced.
• You can also compare edited/added specs between commits with <commit>..<commit>

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...

Here is how to switch your Selenium to Chrome:

1. 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.

2. 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...

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...

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...