Effective Testing with RSpec 3

Filling In the First Spec

You don’t have any classes or methods yet for indicating whether recording an expense succeeded or failed. Let’s take a moment to sketch out what that code would look like.

Connecting to Storage

First, you’ll need some kind of storage engine that keeps the expense history; call it a Ledger. The simplest approach would be for the API class to create a Ledger instance directly:

05-unit-specs/03/expense_tracker/api_snippets.rb

class API < Sinatra::Base
  def initialize
    @ledger = Ledger.new
    super() # rest of initialization from Sinatra
  end
end

# Later, callers do this:
app = API.new

But this style limits the code’s flexibility and testability, as it doesn’t allow you to use a substitute ledger for ...