Built-in support for Rails and Bootstrap error classes reduces step overrides, while configurable error classes, XPath selectors, and optional negation improve flexibility.

Quoted CSS attribute selectors let Capybara check meta tags reliably; unquoted values can trigger Nokogiri CSS syntax errors.

Blueprint attributes in Machinist can keep inherited values unless nil is wrapped in a block; editor { nil } clears the master value, plain nil does not.

Capybara's save_and_open_page files can clutter the Rails root when debugging Cucumber scenarios. Set Capybara.save_and_open_page_path to store them elsewhere.

RSpec one-liners can assert expectations on subject with implicit example descriptions, using should or is_expected in expect-based syntax.

Run one RSpec example group or a single it example by line number in a long spec without executing the whole file.

Unfortunately, by default plugin tests are pretty bland. They use the plain unit test suite supplied by Ruby, and not any of the extended Rails test framework. This will leave our plugin’s test classes with no access to fixtures, database.yml configuration, or any of those nice class auto-loading features.

Template and eval coverage in Ruby can be tracked with SimpleCov from Ruby 3.2 onward, including Haml and ERB templates.

rails_admin specs can pass with rspec but fail under rake spec; setting ENV['SKIP_RAILS_ADMIN_INITIALIZER'] = 'false' in spec_helper restores the initializer.

Analytics tracking can be hard to verify in the browser; a Chrome extension swaps in a debug version and prints tracking details to the JavaScript console.

mathn can make rspec_spinner and cucumber_spinner loop forever while rendering the progress bar.

Validate Apache configuration syntax with apache2ctl configtest or apache2ctl -t; passing checks do not guarantee a successful server start.

Quickly verify that a JavaScript Sentry setup reports browser errors by triggering a deliberate exception in a click handler.

Check which packages and versions apt would install before making changes. --dry-run simulates upgrades without touching the system.

Avoid Cucumber::Ambiguous by defining a more specific step that overrides a generic one in Spreewald 1.5.0+.

display conflicts with a reserved Machinist blueprint name, so a blueprint attribute using that label may fail unexpectedly.

Shared setup adds context to scenarios in a feature and runs before each scenario, after Before hooks.

Release candidate and beta gem versions are treated as pre-releases and are ignored unless explicitly requested; RubyGems converts dash-separated SemVer pre-release tags to dot-separated versions.

Publish npm pre-release versions on a separate tag so stable users do not receive alpha or beta builds by default.

Timecop 0.3.4 and earlier can create records with timestamps in the past after Timecop.freeze; upgrading to 0.3.5 avoids the bug.

Custom RSpec matcher for verifying delegated methods in Ruby models, including prefixed delegation like author_name.

Webrat can submit a page request as POST by passing :post to visit, useful when a path must be tested with form-style submission.