These are some key takeaways from the 3rd course for me based on the curriculum as well as the feedback received from the TAs for every module (aka Week).

• to keep controllers skinny
• ActiveRecord transactions (all or none!)
• RSpec macros and shared_examples
• Capybara introduction and first feature spec

Module 3

• Outside-in development in action with feature-specs in Capybara: Starting with a feature-spec (BDD) and letting it drive the design (models/routes/controllers) seems to be coming a bit more naturally to me than the other way round
• Single-Assertion Principle can (and should) be violated in feature-specs: not just to DRY up the code, but mainly because feature specs are expensive to run!
• ActiveRecord transactions was one of the primary learnings when trying to update the video positions in the queue. Got introduced to ACID, thanks to the missus!
• RSpec shared_examples and macros are very helpful in DRYing up the specs.
• Got re-exposed to :xpath based search of elements in the view template! DOM tree, XPath, had heard and read about these a long time ago for some thing totally different!

Finer points:

• QueueItem.find_by(id: params[:id], user: current_user) does not throw a “RecordNotFound” exception in rails. Doing this current_user.queue_items.find(params[:id]) does. Use either knowingly!
• Do not prefix method names with get_ or set_. Instead come up with better names to indicate what they do.
• Use method: delete instead of the default get for destroying a record so that the route cannot be bookmarked.
• Use find_by instead of where(...).first for searching a single record.
• Prefix self. when assigning value to an instance variable but it is not necessary when using the variable in an instance method.

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