While verifying doubles in RSpec is a good default, it is limited in the amount of methods it actually is...

There is a way to use multiple databases in Rails. You may have asked yourself how you're able to...

You can use Unpoly's up.on with a named listener function and immediately unbind this event listener with { once: true...

Redis.current will be removed without replacement in redis-rb 5.0. Version 4.6.0 adds deprecation warnings for Redis.current and Redis.current=: `Redis.current...

RSpec's let allows you to super into "outside" definitions, in parent contexts. Example: describe '#save' do subject { described_class.new(attributes...

To ensure a consistent code style for JavaScript code, we use ESLint. The workflow is similar to integrating rubocop...

Attaching files to a field that is handled by Carrierwave uploaders (or maybe any other attachment solution for Rails) in...

When Capybara locates elements in the DOM, by default it allows only accessing visible elements -- when you are using a...

Jasmine is a great tool to unit test your JavaScript components without writing an expensive end-to-end test for...

Learn to create test data effectively using factories. Decouple tests by having each test start with an empty database...

RSpec Rails can automatically mix in different behaviors to your tests based on their type tag, for example enabling you...

You can use RSpec::Matchers.define_negated_matcher to define a negated version of an existing matcher. This is particularly useful...

Jasmine is a great way to unit test your JavaScript components without writing an expensive end-to-end test for...

A flaky test is a test that is often green, but sometimes red. It may only fail on some PCs...

Basic validations Read the Rails Guide on ActiveRecord Validations. You should have an overview which kinds of validations are built...

Within development and test environments, Rails is usually configured to show a detailed debug page instead of 404s. However, there...

This RailsCast demonstrated a very convenient method to activate VCR for a spec by simply tagging it with :vcr.

RSpec is smart when using the include-matcher in combination with .not_to. One could assume that .not_to include...

Besides their default styling properties, HTML elements have a semantic meaning. For example, an h1 tag is usually styled with...

The RSpec matcher tests if two HTML fragments are equivalent. Equivalency means: Whitespace is ignored Types of attribute quotes are...

Given you have a strict CSP that only allows elements from your own domain: Content-Security-Policy: script-src 'self' This will block JavaScript handlers inlined as attribute into your HTML elements. Clicking on the following link will only log an error with a strict CSP: click me click me Solution 1: Move the handler into your JavaScript The recommended solution is to move the handler from the HTML to the allowed JavaScript file that we loaded via . In the example above we could invent a new [data-alert] attribute with the alert message: click me Then our JavaScript intercepts clicks on elements with that attribute: document.addEventListener('click', function(event) { let link = event.target.closest('[data-alert]') if (link) { let message = link.dataset.alert alert(message) event.preventDefault() } }) Solution 2: Allow that one handler in your CSP Some browsers allow the CSP directive script-src-attr. This lets you allow the hashes of actual JavaScript code. The SHA256 hash of alert('hello') is vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE= (in Base64). We can allow this one event handlers like this: Content-Security-Policy: script-src 'self'; script-src-attr 'unsafe-hashes' 'sha256-vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE=' Note the sha256- prefix. This event handler now works when clicked: click me But any other script will still be blocked: click me Dealing with legacy browsers Currently (November 2023) about 75% of browsers support script-src-attr. Here is a forward-looking compromise that many users use with new CSP features: Have a liberal CSP with old directives supported by all browsers Make your CSP stricter with new, more specific directives for browsers that support it The CSP spec supports that approach in that using newer, more specific directives disable older, more general features. In our case this means: For old browsers, allow all inline scripts For new browsers, disallow inline scripts but allow inline handlers with given hashes Here is a CSP directive that works like this: Content-Security-Policy: script-src 'self' 'unsafe-inline'; script-src-elem 'self'; script-src-attr 'unsafe-hashes' 'sha256-vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE=' Old browsers will only use script-src. New browsers will use script-src-elem (for tags) and script-src-attr (for inline event handlers), which override the more liberal rules from script-src.

If you have a flaky command you can use the nick-invision/retry to re-try a failing command, optionally...

We recently noticed issues with Chrome 75+ when having the w3c option enabled within the Selenium webdriver. It looks like...