WIP: Don't allow album release date to be in the future

TODO: We need to decide what to do about the 2 existing albums that this
would render invalid.

app/models/album.rb

@@ -8,6 +8,7 @@ class Album < ApplicationRecord
 
   validates :title, presence: true
   validates :price, presence: true, numericality: true
+  validates :released_on, comparison: { less_than_or_equal_to: Time.zone.today, allow_blank: true }
 
   belongs_to :artist
   has_many :tracks, -> { order(position: :asc) }, dependent: :destroy, inverse_of: :album

test/models/album_test.rb

@@ -213,4 +213,12 @@ class AlbumTest < ActiveSupport::TestCase
     assert_not album.valid?
     assert_includes album.errors[:cover], 'must be an image file (jpeg, png)'
   end
+
+  test 'is not valid if released_on is a date in the future' do
+    freeze_time do
+      album = build(:album, released_on: 1.day.from_now)
+      assert_not album.valid?
+      assert_includes album.errors[:released_on], "must be less than or equal to #{Time.zone.today}"
+    end
+  end
 end