Create a custom matcher for the database anonymizer spec

Previously, the tests were only really asserting that ANY
of the scrubbable fields had changed, rather than guaranteeing
that ALL of them have changed. Now, a test should fail if
any of the fields declared to be scrubbed didn't get scrubbed.

spec/services/database_anonymizer_spec.rb

@@ -1,6 +1,39 @@
 require 'rails_helper'
 
 describe DatabaseAnonymizer do
+  RSpec::Matchers.define :scrub_fields do |record, fields|
+    match do |actual|
+      original_attributes = record.attributes.slice(*fields.map(&:to_s))
+      unless original_attributes.present?
+        raise "Could not determine original attributes"
+      end
+
+      actual.call
+
+      processed_attributes = record.attributes.slice(*fields.map(&:to_s))
+
+      @unscrubbed_attributes = []
+      original_attributes.each do |key, value|
+        if processed_attributes[key] == value
+          @unscrubbed_attributes << key
+        end
+      end
+
+      @unscrubbed_attributes.length == 0
+    end
+
+    failure_message do |actual|
+      <<~EOT
+          Did not seem to scrub these #{record.class} attributes:
+          #{@unscrubbed_attributes.join(', ')}
+      EOT
+    end
+
+    def supports_block_expectations?
+      true
+    end
+  end
+
   describe '#anonymize_database' do
     let(:logger) { Logger.new(STDOUT) }
     let(:anonymizer) { DatabaseAnonymizer.new(logger) }
@@ -61,79 +94,116 @@
   describe '#anonymize_user' do
     it 'replaces identifying data for non-admin users' do
       user = create(:user)
-      expect { DatabaseAnonymizer.new.anonymize_user(user) }.to change{ [user.email,
-                                                                     user.first_name,
-                                                                     user.last_name,
-                                                                     user.gender,
-                                                                     user.password] }
+      anonymized_fields = [
+        :email,
+        :first_name,
+        :last_name,
+        :password
+      ]
+      expect {
+        DatabaseAnonymizer.new.anonymize_user(user)
+      }.to scrub_fields(user, anonymized_fields)
     end
 
     it 'does not replace data for a sample admin user' do
       user = create(:user)
       user.email = 'admin@example.com'
-      expect { DatabaseAnonymizer.new.anonymize_user(user) }.to_not change{ [user.email, user.password] }
+      expect { DatabaseAnonymizer.new.anonymize_user(user) }.to_not change { user.attributes }
     end
 
     it 'does not replace data for a sample organizer user' do
       user = create(:user)
       user.email = 'organizer@example.com'
-      expect { DatabaseAnonymizer.new.anonymize_user(user) }.to_not change{ [user.email, user.password] }
+      expect { DatabaseAnonymizer.new.anonymize_user(user) }.to_not change { user.attributes }
     end
   end
 
   describe '#anonymize_meetup_user' do
     it 'replaces identifying data from Meetup User data' do
       user = create(:meetup_user)
-      expect{ DatabaseAnonymizer.new.anonymize_meetup_user(user) }.to change{ [user.full_name,
-                                                                         user.meetup_id ] }
+      anonymized_fields = [
+        :full_name,
+        :meetup_id
+      ]
+      expect {
+        DatabaseAnonymizer.new.anonymize_meetup_user(user)
+      }.to scrub_fields(user, anonymized_fields)
     end
   end
 
   describe '#anonymize_survey' do
     it 'replaces identifying data from Survey data' do
       survey = create(:survey)
-      expect{ DatabaseAnonymizer.new.anonymize_survey(survey) }.to change{ [ survey.good_things,
-                                                                         survey.bad_things,
-                                                                         survey.other_comments ] }
+      anonymized_fields = [
+        :good_things,
+        :bad_things,
+        :other_comments
+      ]
+      expect {
+        DatabaseAnonymizer.new.anonymize_survey(survey)
+      }.to scrub_fields(survey, anonymized_fields)
     end
   end
 
   describe '#anonymize_rsvp' do
     it 'replaces identifying data from RSVP data' do
-      rsvp = create(:rsvp)
-      expect{ DatabaseAnonymizer.new.anonymize_rsvp(rsvp) }.to change{ [ rsvp.subject_experience,
-                                                                     rsvp.teaching_experience,
-                                                                     rsvp.job_details,
-                                                                     rsvp.childcare_info,
-                                                                     rsvp.plus_one_host,
-                                                                     rsvp.dietary_info ] }
+      rsvp = create(:rsvp, plus_one_host: Faker::Name.name)
+      anonymized_fields = [
+        :subject_experience,
+        :teaching_experience,
+        :job_details,
+        :childcare_info,
+        :plus_one_host,
+        :dietary_info
+      ]
+      expect {
+        DatabaseAnonymizer.new.anonymize_rsvp(rsvp)
+      }.to scrub_fields(rsvp, anonymized_fields)
     end
   end
 
   describe '#anonymize_profile' do
     it 'replaces identifying data from the Profile' do
       profile = create(:user).profile
-      profile.update_attribute(:github_username, Faker::Hacker.noun.gsub('', '-'))
-      profile.update_attribute(:twitter_username, 'fake_username')
-      expect{ DatabaseAnonymizer.new.anonymize_profile(profile) }.to change{ [ profile.other,
-                                                                           profile.github_username,
-                                                                           profile.bio ]}
+      profile.update_attributes(
+        github_username: Faker::Hacker.noun.gsub('', '-'),
+        twitter_username: 'fake_username'
+      )
+      anonymized_fields = [
+        :other,
+        :github_username,
+        :twitter_username,
+        :bio
+      ]
+      expect {
+        DatabaseAnonymizer.new.anonymize_profile(profile)
+      }.to scrub_fields(profile, anonymized_fields)
     end
   end
 
   describe '#anonymize_location' do
     it 'replaces sensitive data from the Location' do
       location = create(:location, notes: 'fun place', contact_info: 'someone important')
-      expect{ DatabaseAnonymizer.new.anonymize_location(location) }.to change{ [ location.notes,
-                                                                           location.contact_info ]}
+      anonymized_fields = [
+        :notes,
+        :contact_info
+      ]
+      expect {
+        DatabaseAnonymizer.new.anonymize_location(location)
+      }.to scrub_fields(location, anonymized_fields)
     end
   end
 
   describe '#anonymize_event_email' do
     it 'replaces sensitive data from the email' do
       event_email = create(:event_email, subject: 'hello', body: 'this is some info')
-      expect{ DatabaseAnonymizer.new.anonymize_event_email(event_email) }.to change{ [ event_email.subject,
-                                                                           event_email.body ]}
+      anonymized_fields = [
+        :subject,
+        :body
+      ]
+      expect {
+        DatabaseAnonymizer.new.anonymize_event_email(event_email)
+      }.to scrub_fields(event_email, anonymized_fields)
     end
   end
 end