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This coding exercise comes from Upcase, the online learning platform we run. It's part of the Refactoring course and is just one small sample of all the great material available on Upcase, so be sure to visit and check out the rest.
In this exercise, you'll be breaking out a value object from the ReportCard class.
Value Objects are objects that represent a value (such as a phone number or email address) rather than a unique, identifiable entity (such as a particular user in the system).
Value Objects are defined in terms of their contents, and are therefore immutable. Objects are things that have an identity, and may have different values over time. A User object, for example, might change its username attribute and still be the same object. An Address value object, on the other hand, cannot change. Changing the attributes of an Address instance make it a different object entirely.
Value Objects often implement information derived from a primitive object, such as the dollars and cents from a float, or the user name and domain from an email string.
You can learn more about Value Objects from The Weekly Iteration.
To start, you'll want to clone and run the setup script for the repo
git clone [email protected]:thoughtbot-upcase-exercises/extract-value-object.git
cd extract-value-object
bin/setup
Extract a new grade value object from ReportCard (located at lib/report_card.rb). Make sure to add additional tests for the new object as you go.
Make sure all tests are passing by running:
rake
Check out the featured solution branch to see the approach we recommend for this exercise.
If you find yourself stuck, be sure to check out the associated Upcase Forum discussion for this exercise to see what other folks have said.
When you've finished the exercise, head on back to the Refactoring course to find the next exercise, or explore any of the other great content on Upcase.
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