Refactor and add test `failure: a vote should not include an answer v…

…alue that is not present in the ballot`.

lib/flick/votes.ex

@@ -4,6 +4,7 @@ defmodule Flick.Votes do
   a specific `Flick.Ballots.Ballot`.
   """
 
+  alias Flick.Ballots.Ballot
   alias Flick.Repo
   alias Flick.Votes.Vote
 
@@ -12,8 +13,10 @@ defmodule Flick.Votes do
   @doc """
   Records a vote for the given `Flick.Ballots.Ballot` entity.
   """
-  @spec record_vote(map()) :: {:ok, Vote.t()} | {:error, changeset()}
-  def record_vote(attrs) do
+  @spec record_vote(Ballot.t(), map()) :: {:ok, Vote.t()} | {:error, changeset()}
+  def record_vote(ballot, attrs) do
+    attrs = Map.put(attrs, "ballot_id", ballot.id)
+
     %Vote{}
     |> Vote.changeset(attrs)
     |> Repo.insert()

lib/flick/votes/vote.ex

@@ -6,6 +6,7 @@ defmodule Flick.Votes.Vote do
   use Ecto.Schema
 
   import Ecto.Changeset
+  import FlickWeb.Gettext
 
   alias Flick.Ballots.Ballot
   alias Flick.Votes.Answer
@@ -46,9 +47,40 @@ defmodule Flick.Votes.Vote do
       drop_param: :answers_drop,
       required: true
     )
+    |> validate_answers_are_present_in_ballot()
     |> validate_answers_question_uniqueness()
   end
 
+  defp validate_answers_are_present_in_ballot(changeset) do
+    validate_change(changeset, :answers, fn :answers, new_answers ->
+      ballot = Flick.Ballots.get_ballot!(get_field(changeset, :ballot_id))
+      # For each of the answers, make sure each ranked answer is present in the
+      # possible answers for the question from the ballot.
+      Enum.reduce(new_answers, [], fn changeset, acc ->
+        question_id = get_field(changeset, :question_id)
+        ranked_answers = get_field(changeset, :ranked_answers)
+        question_from_ballot = Enum.find(ballot.questions, &(&1.id == question_id))
+
+        case question_from_ballot do
+          nil ->
+            [answers: "question_id not found in ballot"]
+
+          question ->
+            possible_answers = String.split(question.possible_answers, ",")
+            invalid_answers = Enum.reject(ranked_answers, &Enum.member?(possible_answers, &1))
+
+            if invalid_answers == [] do
+              acc
+            else
+              error_label = ngettext("invalid answer", "invalid answers", length(invalid_answers))
+              error_description = Enum.join(invalid_answers, ", ")
+              [answers: "#{error_label}: #{error_description}"]
+            end
+        end
+      end)
+    end)
+  end
+
   defp validate_answers_question_uniqueness(changeset) do
     validate_change(changeset, :answers, fn :answers, new_answers ->
       question_ids =

test/flick/votes_test.exs

@@ -31,8 +31,7 @@ defmodule Flick.VotesTest do
       question_id = hd(published_ballot.questions).id
 
       assert {:ok, vote} =
-               Votes.record_vote(%{
-                 "ballot_id" => published_ballot_id,
+               Votes.record_vote(published_ballot, %{
                  "answers" => [
                    %{
                      "question_id" => question_id,
@@ -59,8 +58,7 @@ defmodule Flick.VotesTest do
       question_id = hd(published_ballot.questions).id
 
       assert {:ok, vote} =
-               Votes.record_vote(%{
-                 "ballot_id" => published_ballot_id,
+               Votes.record_vote(published_ballot, %{
                  "answers" => [
                    %{
                      "question_id" => question_id,
@@ -83,11 +81,8 @@ defmodule Flick.VotesTest do
     test "failure: a vote must answer all ballot questions", %{
       published_ballot: published_ballot
     } do
-      published_ballot_id = published_ballot.id
-
       assert {:error, changeset} =
-               Votes.record_vote(%{
-                 "ballot_id" => published_ballot_id,
+               Votes.record_vote(published_ballot, %{
                  "answers" => []
                })
 
@@ -97,11 +92,8 @@ defmodule Flick.VotesTest do
     test "failure: a vote can only have a single answer per ballot question", %{
       published_ballot: published_ballot
     } do
-      published_ballot_id = published_ballot.id
-
       assert {:error, changeset} =
-               Votes.record_vote(%{
-                 "ballot_id" => published_ballot_id,
+               Votes.record_vote(published_ballot, %{
                  "answers" => [
                    %{
                      "question_id" => hd(published_ballot.questions).id,
@@ -117,7 +109,22 @@ defmodule Flick.VotesTest do
       assert "should not include duplicate question ids" in errors_on(changeset).answers
     end
 
-    # test "failure: a answer must align to a know answer option of the ballot" do
-    # end
+    test "failure: a vote should not include an answer value that is not present in the ballot",
+         %{
+           published_ballot: published_ballot
+         } do
+      attrs = %{
+        "answers" => [
+          %{
+            "question_id" => hd(published_ballot.questions).id,
+            "ranked_answers" => ["Forbidden Hot Dogs", "Illegal Cookies"]
+          }
+        ]
+      }
+
+      assert {:error, changeset} = Votes.record_vote(published_ballot, attrs)
+
+      assert "invalid answers: Forbidden Hot Dogs, Illegal Cookies" in errors_on(changeset).answers
+    end
   end
 end