Hi all, I am reading the Programming Phoenix book and following the steps to implement the Rumbl webapp.

Then at some steps I try to add something custom to learn a bit more.

So in that application, I have a controller which renders a template like this:

Listing videos

  <td class="text-right">
    <%= link "Show", to: video_path(@conn, :show, video), class: "btn btn-default btn-xs" %>
    <%= link "Edit", to: video_path(@conn, :edit, video), class: "btn btn-default btn-xs" %>
    <%= link "Delete", to: video_path(@conn, :delete, video), method: :delete, data: [confirm: "Are you sure?"], class: "btn btn-danger btn-xs" %>
  </td>
</tr>

<% end %>

<%= link “New video”, to: video_path(@conn, :new) %>

I added this line to render the categories <%= if category = video.category, do: category.name %>

This is my controller
def index(conn, _params, user) do
videos = Repo.all(user_videos(user)) |> Repo.preload(:category)
render(conn, “index.html”, videos: videos)
end

defp user_videos(user) do
# query user videos
assoc(user, :videos)
end

And when I run a test I wrote, this one:

test “renders index.html”, %{conn: conn} do
videos = [%Rumbl.Video{id: “1”, title: “dogs”},
%Rumbl.Video{id: “2”, title: “cats”}]
content = render_to_string(Rumbl.VideoView, “index.html”,
conn: conn, videos: videos)

assert String.contains?(content, "Listing videos")
for video <- videos do
  assert String.contains?(content, video.title)
end

end

It complains with categories not being preloaded

** (KeyError) key :name not found in: #Ecto.Association.NotLoaded

I also tried this:

defp user_videos(user) do
query = (from u in user, select: u.videos, preload: [:category])
Repo.all(query)
end

But not working neither, so how can I preload them?

I thought I just needed to preload them at the pipe with |> Repo.preload(:category)

Also the strange thing is this started to crash with test, without the test it renders the index.html template without any issue