Add specs for BlackListedEmailValidator (#9651)

* Add specs for BlackListedEmailValidator

* Use instance variable

app/validators/blacklisted_email_validator.rb

@@ -2,31 +2,32 @@
 
 class BlacklistedEmailValidator < ActiveModel::Validator
   def validate(user)
-    user.errors.add(:email, I18n.t('users.invalid_email')) if blocked_email?(user.email)
+    @email = user.email
+    user.errors.add(:email, I18n.t('users.invalid_email')) if blocked_email?
   end
 
   private
 
-  def blocked_email?(value)
-    on_blacklist?(value) || not_on_whitelist?(value)
+  def blocked_email?
+    on_blacklist? || not_on_whitelist?
   end
 
-  def on_blacklist?(value)
-    return true if EmailDomainBlock.block?(value)
+  def on_blacklist?
+    return true if EmailDomainBlock.block?(@email)
     return false if Rails.configuration.x.email_domains_blacklist.blank?
 
     domains = Rails.configuration.x.email_domains_blacklist.gsub('.', '\.')
     regexp  = Regexp.new("@(.+\\.)?(#{domains})", true)
 
-    value =~ regexp
+    @email =~ regexp
   end
 
-  def not_on_whitelist?(value)
+  def not_on_whitelist?
     return false if Rails.configuration.x.email_domains_whitelist.blank?
 
     domains = Rails.configuration.x.email_domains_whitelist.gsub('.', '\.')
     regexp  = Regexp.new("@(.+\\.)?(#{domains})$", true)
 
-    value !~ regexp
+    @email !~ regexp
   end
 end

spec/validators/blacklisted_email_validator_spec.rb

+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe BlacklistedEmailValidator, type: :validator do
+  describe '#validate' do
+    let(:user)   { double(email: 'info@mail.com', errors: errors) }
+    let(:errors) { double(add: nil) }
+
+    before do
+      allow_any_instance_of(described_class).to receive(:blocked_email?) { blocked_email }
+      described_class.new.validate(user)
+    end
+
+    context 'blocked_email?' do
+      let(:blocked_email) { true }
+
+      it 'calls errors.add' do
+        expect(errors).to have_received(:add).with(:email, I18n.t('users.invalid_email'))
+      end
+    end
+
+    context '!blocked_email?' do
+      let(:blocked_email) { false }
+
+      it 'not calls errors.add' do
+        expect(errors).not_to have_received(:add).with(:email, I18n.t('users.invalid_email'))
+      end
+    end
+  end
+end