Refactoring - Null Object: Part One

Exercise Questions
1

This topic is for the [Null Object - Part One] exercise in the [Refactoring] trail. Post any questions, corrections, or pointers you have to share with other Upcase subscribers.
[Null Object - Part One]: https://exercises.upcase.com/exercises/null-object-part-one
[Refactoring]: Refactoring Code | Code Refactoring Online Tutorial by thoughtbot

2

Rake tests did not work upon cloning:

I found I needed to specify the rspec version in the Gemfile, and then a test failed.

Failures:

  1. User#has_mentoring? returns false without a subscription
    Failure/Error: expect(user.has_mentoring?).to be_false
    expected to respond to false? or perhaps you meant be false or be_falsey

    ./spec/user_spec.rb:36:in `block (3 levels) in <top (required)>ā€™

This was before any changes to the file. If anyone has any similar issues, let me know.

3

Which RSpec version did you specify?

4

Sorry, Andy. That would have been helpful information.

The version was not specified in the original gemfile, but it was 2.14.4. I updated to 3.3.0. Then I received the following deprecations and failures when I called rake.

Failures:

1) User#has_mentoring? returns false without a subscription
Failure/Error: expect(user.has_mentoring?).to be_false
expected to respond to false? or perhaps you meant be false or be_falsey
# ./spec/user_spec.rb:36:in `block (3 levels) in <top (required)>ā€™

Deprecation Warnings:

Using stub from rspec-mocksā€™ old :should syntax without explicitly enabling the syntax is deprecated. Use the new :expect syntax or explicitly enable :should instead. Called from /Users/gwendolyn/Code/upcase/null-object-part-one/spec/subscription_spec.rb:26:in `block (3 levels) in <top (required)>'.

If you need more of the backtrace for any of these deprecations to
identify where to make the necessary changes, you can configure
config.raise_errors_for_deprecations!, and it will turn the
deprecation warnings into errors, giving you the full backtrace.

1 deprecation warning total

Finished in 0.17634 seconds (files took 2.96 seconds to load)
9 examples, 1 failure

Failed examples:

rspec ./spec/user_spec.rb:33 # User#has_mentoring? returns false without a subscription

5

Is the sha 81e4aea24c8576fe7794e5343907849bf9eff811?

6

I needed to update RSpec

bundle update rspec

and then in spec/user_spec.rb I changed the test ā€˜returns false without a subscriptionā€™ that was complaining about to_be_false to to_be_falsy. After that I was green again.

1 Like
7

Thanks for this!

1 Like
9

on respc 3.4.0 i also needed to update the following, in addition to edā€™s falsy change:

On line 8 of user_spec.rb:
subscription.stub(:charge)
to
allow(subscription).to receive(:charge)

And then on line 26 subsciption_spec.rb:
credit_card.stub(:charge)
to
allow(credit_card).to receive(:charge)

10

Iā€™m having issues with failing tests for a solution Iā€™d think would work. I keep getting ā€œstack too deepā€ errors. Hereā€™s my refactored User class. It seems like the subscription override is making them go haywire. Any thoughts?

class User
  include ActiveModel::Model
  attr_accessor :credit_card, :subscription

  def subscription
    subscription || NoSubscription.new
  end

  def charge
    subscription.charge(credit_card)
  end

  def has_mentoring?
    subscription.mentoring
  end

  def price
    subscription.price
  end
end
11

In the subscription method, reference it locally by using the instance version

@subscription || NoSubscription.new

Current version is calling itself, causing an infinite loop.

12

Thank you! That was exactly the problem. Silly mistake on my part :grin:

1 Like