Remove redundant max_votes validation from Poll::Answer

Since commit 8deb1964b, the `WebVote` class enforces the maximum vote
validation, making the `max_votes` method in `Poll::Answer` redundant.

app/models/poll/answer.rb

@@ -9,21 +9,9 @@ class Poll::Answer < ApplicationRecord
   validates :author, presence: true
   validates :answer, presence: true
   validates :option, uniqueness: { scope: :author_id }, allow_nil: true
-  validate :max_votes
-
   validates :answer, inclusion: { in: ->(poll_answer) { poll_answer.option.possible_answers }},
                      if: ->(poll_answer) { poll_answer.option.present? }
 
   scope :by_author, ->(author_id) { where(author_id: author_id) }
   scope :by_question, ->(question_id) { where(question_id: question_id) }
-
-  private
-
-    def max_votes
-      return if !question || !author || persisted?
-
-      if question.answers.by_author(author).count >= question.max_votes
-        errors.add(:answer, "Maximum number of votes per user exceeded")
-      end
-    end
 end

spec/models/poll/answer_spec.rb

@@ -37,27 +37,6 @@ describe Poll::Answer do
       expect(answer).not_to be_valid
     end
 
-    it "is not valid if there's already an answer to that question" do
-      author = create(:user)
-      question = create(:poll_question, :yes_no)
-
-      create(:poll_answer, author: author, question: question)
-
-      answer = build(:poll_answer, author: author, question: question)
-
-      expect(answer).not_to be_valid
-    end
-
-    it "is not valid when user already reached multiple answers question max votes" do
-      author = create(:user)
-      question = create(:poll_question_multiple, :abc, max_votes: 2)
-      create(:poll_answer, author: author, question: question, answer: "Answer A")
-      create(:poll_answer, author: author, question: question, answer: "Answer B")
-      answer = build(:poll_answer, author: author, question: question, answer: "Answer C")
-
-      expect(answer).not_to be_valid
-    end
-
     it "is not valid when there are two identical answers" do
       author = create(:user)
       question = create(:poll_question_multiple, :abc)

spec/models/poll/web_vote_spec.rb

@@ -44,6 +44,21 @@ describe Poll::WebVote do
       expect(voter.poll_id).to eq answer.poll.id
     end
 
+    it "updates existing multiple options instead of adding new ones" do
+      question = create(:poll_question_multiple, :abc, poll: poll, max_votes: 2)
+      option_a = question.question_options.find_by(title: "Answer A")
+      option_b = question.question_options.find_by(title: "Answer B")
+      option_c = question.question_options.find_by(title: "Answer C")
+
+      create(:poll_answer, author: user, question: question, option: option_a)
+      create(:poll_answer, author: user, question: question, option: option_b)
+
+      web_vote.update(question.id.to_s => { option_id: [option_c.id.to_s] })
+
+      expect(question.reload.answers.size).to eq 1
+      expect(question.reload.answers.first.option).to eq option_c
+    end
+
     it "does not save the answer if the voter is invalid" do
       allow_any_instance_of(Poll::Voter).to receive(:valid?).and_return(false)
 
@@ -55,6 +70,28 @@ describe Poll::WebVote do
       expect(question.answers).to be_blank
     end
 
+    it "does not save the answer if it exceeds the allowed max votes" do
+      question = create(:poll_question_multiple, :abc, poll: poll, max_votes: 2)
+
+      result = web_vote.update(question.id.to_s => { option_id: question.question_options.ids.map(&:to_s) })
+
+      expect(result).to be false
+      expect(poll.voters).to be_blank
+      expect(question.answers).to be_blank
+    end
+
+    it "does not save the answer if unique question receives multiple options" do
+      question = create(:poll_question, :yes_no, poll: poll)
+
+      result = web_vote.update(
+        question.id.to_s => { option_id: question.question_options.ids.map(&:to_s) }
+      )
+
+      expect(result).to be false
+      expect(poll.voters).to be_blank
+      expect(question.answers).to be_blank
+    end
+
     it "creates a voter but does not create answers when leaving everything blank" do
       web_vote.update({})