Describes and executes the rules for determining the cost of a cab ride given some inputs. Relatively SOLID.
The Ember app has no logic/tests/validations, just model, template, binding. The TripsController's GET calculates the trip's cost and returns it in the response. It uses the FareCalculator with tests which uses the ICalculationRules with tests. Lastly, this particular RuleFactory is integration tested here.