Extract method to fetch all the notifications for a card for a given user

We'll need to handle access changes

app/models/card/readable.rb

@@ -7,17 +7,15 @@ module Card::Readable
     end
   end
 
+  def notifications_for(user)
+    scope = user.notifications.unread
+    scope.where(source: event_notification_sources)
+      .or(scope.where(source: mention_notification_sources))
+  end
+
   private
-    def notifications_for(user)
-      user.notifications.unread.where(source: notification_sources)
-    end
-
-    def notification_sources
-      event_notification_sources + mention_notification_sources
-    end
-
     def event_notification_sources
-      events + comment_creation_events
+      events.or(comment_creation_events)
     end
 
     def comment_creation_events
@@ -25,7 +23,7 @@ module Card::Readable
     end
 
     def mention_notification_sources
-      mentions + comment_mentions
+      mentions.or(comment_mentions)
     end
 
     def comment_mentions

test/models/card/readable_test.rb

@@ -26,4 +26,38 @@ class Card::ReadableTest < ActiveSupport::TestCase
       cards(:layout).read_by(users(:kevin))
     end
   end
+
+  test "notifications for a given user" do
+    # Returns card event notifications
+    kevin_notifications = cards(:logo).notifications_for(users(:kevin))
+    assert_includes kevin_notifications, notifications(:logo_published_kevin)
+    assert_includes kevin_notifications, notifications(:logo_assignment_kevin)
+
+    # Returns comment creation event notifications
+    layout_notifications = cards(:layout).notifications_for(users(:kevin))
+    assert_includes layout_notifications, notifications(:layout_commented_kevin)
+
+    # Returns card mention notifications
+    david_notifications = cards(:logo).notifications_for(users(:david))
+    assert_includes david_notifications, notifications(:logo_card_david_mention_by_jz)
+
+    # Returns comment mention notifications
+    assert_includes david_notifications, notifications(:logo_comment_david_mention_by_jz)
+
+    # Only returns unread notifications
+    notifications(:logo_published_kevin).read
+    kevin_notifications_after_read = cards(:logo).notifications_for(users(:kevin))
+    assert_not_includes kevin_notifications_after_read, notifications(:logo_published_kevin)
+    assert_includes kevin_notifications_after_read, notifications(:logo_assignment_kevin)
+
+    # Does not include notifications from other cards
+    other_event = events(:text_published)
+    other_notification = users(:kevin).notifications.create!(source: other_event, creator: users(:david))
+    logo_notifications = cards(:logo).notifications_for(users(:kevin))
+    assert_not_includes logo_notifications, other_notification
+
+    # Does not include notifications for other users
+    assert_not_includes kevin_notifications, notifications(:logo_card_david_mention_by_jz)
+    assert_not_includes kevin_notifications, notifications(:logo_comment_david_mention_by_jz)
+  end
 end