Quick RSpec-to-Jasmine 2 reference for matching expectations and mock assertions when switching test style; Jasmine 1.x uses different syntax.

Webpacker integrates webpack with Rails to bundle JavaScript, stylesheets, images, and other assets, with Yarn managing dependencies and loaders handling non-JavaScript files.

File uploads in Rails are easy to misconfigure, causing lost files, public exposure of confidential data, and environment collisions. Existing uploads also need migration when storage paths change.

fake_stripe runs a local Stripe-like server and fake Stripe.js for feature specs, letting purchase flows be tested without external HTTP requests or Stripe sandbox flakiness.

Rails 3 dbconsole misreads -p test and opens the development database unless the environment is passed first.

Enum values can become FactoryBot traits automatically, reducing manual trait definitions and making new roles or states available in tests with less setup.

Geordi 5.4.0 adds geordi branch, MySQL dump speedups, Pivotal Tracker ID support in global config, and fixes for dump load requirements and test processor documentation.

Selenium tests can fail with ActionView::Template::Error and a dump format error for a symbol, often caused by stale cached files in tmp/cache.

Need production or staging data for migration tests without a full database export; mysqldump can dump only selected tables when a complete dump is too large.

Verify that a value was created by a specific constructor in Jasmine with jasmine.any(Klass) instead of direct instance checks.

Custom Cucumber step for checking that a dropdown’s options are in order, with a Capybara matcher for natural sorting.

Testing resource_controller callbacks directly avoids triggering the action path and verifies hook behavior in controller specs.

Capybara can match elements outside body, including head nodes and hidden links, which helps test metadata and feed autodiscovery.

Exact form-field matching in Cucumber prevents false positives from partial values, while wildcards allow flexible contains-style checks.

Rails app boot and test startup become slow as gems grow; Zeus preloads the app so console, server, generate, and specs run in under a second.

Capybara and Cucumber can assert whether a labeled form control is present or absent, with step definitions needing adjustment across older Capybara versions.

Capybara text checks can match a <textarea> instead of rendered page text; filtering to visible static content avoids false positives.

Cucumber step definitions for asserting whether visible link text is present or absent in Webrat or Capybara using selector-based matchers.

Ruby 1.8.7 test runs can fail with Gem::LOADED_SPECS_MUTEX NameError under older Bundler; Bundler 1.16.1 resolves it.

JavaScript has become essential for production applications, but maintainable code still depends on structured design, object-oriented principles, and test-driven development.

Check a download or page response by its MIME type in Cucumber, using Webrat or Capybara; the Selenium webdriver does not support this approach.

Paperclip attachment checks can give false positives because the attribute returns an attachment object. Use exists? to test whether a file is actually attached.

Console input tests are tricky because stubbing Kernel#gets often has no effect. Targeting the object or class that actually calls gets makes terminal input mocks work.

Sidekiq retries can run out silently, leaving failed jobs only in the dead queue. Add explicit notification logic when permanent worker errors exhaust retries.